Half-Life 2

Let's have a look at Half-Life 2. It's a video game from 2004, initially developed for the PC but later ported to games consoles. When it was new the critics loved it; it went on to sell millions of copies, and people still remember it fondly today.

In the intervening years the game's visuals have been upgraded, but nonetheless the Half-Life 2 of 2016 is substantially the same as the 2004 original. I can't think of another game that has aged so well. It has aged better than I have. The characters of Half-Life will not grow old; they remain as they were in 2007, when the game's final expansion pack was released.

Nine years later there is still no news of Half-Life 3. It is one of the great "what-ifs" of computer gaming. Other long-awaited games are either delayed by the collapse of their publisher, as in the case of Shenmue 3, or the work is beset with organisational and technological problems.

Half-Life 3 isn't like that. Developers Valve Software are financially robust, and if any company knows how to turn a failing project around it is Valve. During the early stages of development the first two Half-Life games suffered from a paucity of imagination and an excess of ideas - respectively - but after Valve bulked them out and cut them down they became masterpieces.

All of the screenshots are from Half-Life 2 (the first game looks pretty rough today).

For a variety of reasons too boring to relate I didn't play Half-Life 2 until 2012. It still impressed me. The edges were ragged and the limited scenery occasionally spoke of the early Pentium 4 era, but the game had power. It still has power.

On a technological level the developers knew their engine's limitations, but even beyond that the game is immortal because it has style. Every texture, every model sits on a foundation of intelligent design work; the game was made by people who knew they were making something of worth, and had the time and resources to do it justice, rare qualities in the games industry.

And the pace of change has slowed. I'm old enough to remember when eight years was an eternity in gaming terms. Eight years is the gap between the top-down, two-dimensional Metal Gear 2: Solid Snake and the artistically lit polygons of its PlayStation descendent Metal Gear Solid. Half-Life 2 was developed at a time when the console port of a PC game was no longer an afterthought; it had to be as good as the PC original. Too often this meant simplifying the game for consoles, and then porting the results to the PC with minimal changes.

I don't want to rag on consoles too much. The old saying that "90% of everything is crap" applies to the PC games industry as well. History remembers a small number of classics such as Civilization and Pirates, and forgets that the majority of games were rubbish. But for a few years the good 10% suffered from being forced into a square hole; it was only 80% as good.

Eventually a new wave of powerful consoles kicked things back into gear, but the gaming industry was then faced with the problem of spiralling budgets, creative exhaustion, and a kind of pervasive homogeneity. Action gaming in the late 2000s and early 2010s was the colour of dull sand despite having all the latest shader technology. It held a Heckler and Koch XM8, and there was a cover system, and the player could pay to download an attractive new suit of bulletproof armour. The foliage was nice.

It has happened before. I remember it. In the late 1990s there was a flood of prefab first-person shooters using licensed engines. The few flashes of novelty were drowned out by boring mission packs and rote sequels, until a saviour emerged. I'm talking about Half-Life, the original Half-Life. It came from nowhere and shook everything up. It put the fear into fear-etical physics. The magazines loved it, just as they had loved Grim Fandango and Thief: The Dark Project, which were released within a few weeks of each other. They were all stone-cold classics, but whereas Fandango and Thief sold modestly, Half-Life was a smash hit.

And it was good, objectively good. Good in the same way that David Attenborough is good. I emphasise this because the magazines and the public sometimes get it wrong. Some games make a splash but are quickly forgotten because they just weren't all that. I'm thinking in particular of Spore or everything Peter Molyneaux has been involved with since 1997. Conversely some games grow in stature with the passage of time, even if they were unpopular when they were new. System Shock 2, for example, or cult Game Boy Color platformer Shantae.

Suffice it to say that Half-Life is a rare example of a series where everyone got it right, including the reviewers and the general public. Good job, general public! You can do it. Sometimes you have questionable taste, and sometimes you are led astray, but in my opinion you have limitless potential, and the case of Half-Life you have proved yourself a valuable asset to the team. Whatever happiness you have in your life, I think you've earned it.

Half-Life was Valve's first product. The company had been founded just two years before by Gabe Newell and another bloke, Mike something, who had both worked for Microsoft for ages. Gabe was Microsoft employee number 271. Microsoft famously rewarded its employees with shares, and by 1996 Gabe and Mike were very wealthy men. All you Linux fans who hated Microsoft back in the day; imagine if you had won! There would be no Half-Life, and it would be your fault. You don't play games, and you probably don't care about the rest of us, but you would have made the world less happy and that is why you are evil.

Gabe and his chums could have retired but instead they decided to make some video games. There was a 3D adventure game called Prospero, which went nowhere, and an action game called Quiver. As a privately-owned entity Valve had both the luxury of editorial control and the terror of financial oblivion driving it on. At first the plan was to churn out Quiver as a "fancy Quake total conversion", in the words of designer Ken Birdwell. On a financial level it would have probably recouped its minimal costs, but for whatever reason - pride, a realisation that skimping on development was ultimately a dead end, we will never know - Valve decided that nothing less than greatness was good enough.

The Half-Life games were famous for their setpieces. Instead of throwing a constant stream of monsters at the player, the game saved them up for special battles; the sequel elevated this to a fine art.

At the time 3D first-person shooters were big business, but 3D game engines were complex pieces of technology, so there arose a development model whereby the major players earned money on the side by licensing their 3D engines to other developers. Half-Life was built on top of the technology Id Software had developed for Quake, although Valve's modifications were so extensive that their version of the engine - they called it GoldSrc - ended up a more popular licence than Id's original.

Half-Life's development took so long that it was released shortly after Quake 2, and it's a testament to the team's hard work that the age of the underlying engine wasn't obvious. In particular the first two Quake games spanned the gap between purely software rendering and hardware 3D cards; Half-Life's combination of PowerVR and 3DFX Glide graphics allied to native Windows support dates it to a very narrow time window.

BOXOUT: The Man in the Woman and the Woman in the Man in the Hazard Suit.
Half-Life's star is Gordon Freeman, a cipher who stands in for the player. Throughout the series he wears a Hazardous Environment Suit (HEV). It's one of the game's signature elements. Freeman is a science nerd who nonetheless single-handedly obliterates an alien army and a company of US Marines. In order to give his exploits an air of plausibility the designers gave him a special armoured suit that protects him from bullets, and at least initially they designed the levels so that Gordon takes the baddies by surprise, or encounters soldiers who are already under attack by aliens. At the beginning of the two games Gordon enters the world in civilian clothes; the HEV is his work uniform. It has a computer voice that warns the player when Gordon sustains damage. When he falls a great height there is a loud snap, and the suit voice tells us that she has detected a major fracture and is administering morphine. By the end of the game Gordon is presumably a morphine-addicted mass of bruises and bone fragments, more jelly than man.

The suit is a peculiar thing. Gordon can be hurt, but the suit itself is indestructible. It has a special electrical forcefield that can withstand bullets and cannon shells but as a hazard suit it's surprisingly useless. It doesn't protect Gordon from fire, ice, or radioactive slime, and despite having rubber boots it is vulnerable to electric shocks.

The suit isn't unique to Gordon. We see other scientists wearing it; they often have helmets, but Gordon's helmet exists in a curious limbo. When we see Gordon from outside he doesn't wear one, and none of the other characters mention it during dialogue sequences. At one point soldiers club Gordon on the head, knocking him out, and when he dives underwater his breath only lasts for a few seconds.

But if he's not wearing a helmet, how come no-one shoots at his head?* The alien headcrabs leap at his face but bounce off. How does Gordon hear the suit's radio? If he removes the helmet, where does it go? If he wears it all the time how do the other characters know that they are speaking to Gordon Freeman and not, for example, a beautiful blonde woman called Tuesday Swymwarden? Is the majority of the two games a hallucination caused by Gordon bashing his head at the beginning of Half-Life, having stupidly forgotten to put on his helmet?

* The mundane reason is that the original Half-Life engine didn't support locational damage; it doesn't matter where the baddies hit Gordon, it hurts the same.

These and many other questions are never answered. What does it matter. The Half-Life games aspire to a higher level of realism than other games but the designers knew when to draw the line. The suit dates the game slightly. When Half-Life was new the standard damage model of first-person shooters gave the player a health bar plus a bonus armour bar that reduced the level of damage a player could sustain; in both cases the player replenished his health and armour by running over power-ups. Damage had no effect on the player beyond reducing his health bar and a player on the verge of death could leap just as high as a player who had just joined the game. The "bullet sponge" element nowadays feels old-fashioned. Most subsequent military shooters made the player more vulnerable and tried to model damage to the legs, arms, and head by disabling the player in some way; some games make the player weaker and remove health bonuses, but give the player a damage bar that regenerates. This is just as artificial as forcing the player to gobble up health kits but on a gameplay level it keeps the player moving forward, because there is no longer a reason to backtrack through the level to search for power-ups.

What about the man in the suit? Back in 2010 British movie magazine Empire selected Gordon as the best video game character of all time, a decision that probably puzzled fans of the game. Freeman is, famously, a blank slate. We never hear his voice. The dialogue is written so that the characters constantly tell Gordon things without asking for a reply. Gordon has never appeared in spin-off media and does not have a voice actor. This anonymity isn't actually all that rare in computer games. Nintendo's Mario has a distinctive voice and a simple backstory, but I couldn't tell you anything about his personality; the same goes for the main characters of the System Shock games. Freeman stands out because unlike the hacker of System Shock he has a name, and unlike Mario he isn't a cartoon, he exists in a recreation of the real world.

The events of Half-Life take place over the course of a day, after which Gordon is placed in a hyperspace limbo for twenty years or so; he is woken up and immediately thrust into Half-Life 2, which takes place over the course of three days. From Gordon's point of view he goes to work one morning and then spends the next three days witnessing the apocalypse. It's a wonder that he doesn't go completely mad from a mixture of mental trauma and future shock.

In 2007 a popular YouTube series, Freeman's Mind, elaborated on this idea; the series overdubbed Freeman's imagined internal monologue onto a Let's Play of Half-Life. In Freeman's Mind Gordon begins the game as a petulant, emotionally unstable egoist and ends as a bloodthirsty, paranoid lunatic, which is entirely reasonable given that he is subjected to relentless horror and jeopardy for several hours whilst trapped in a metal suit and pumped full of morphine.

Also, after saving humanity and then agreeing to save humanity again, he has to spend the entirety of the second game running around with the fetching Alyx Vance in her tight, tight jeans, and he doesn't even get a hug. I mean, Luke Skywalker was basically a monk, and Leia was his sister, but Gordon Freeman is not a monk and Alyx Vance is not his sister, if you know what I mean (kissing).

Valve hired a novelist to type up the development team's ideas - novelists are good typists - and after taking a long hard look at what they had developed they concluded that it was still not enough. So the story goes, the original design had a few good elements but they were spread very thinly; the team squashed everything into a single level, which was awesome, and from that point they knew that they had their work cut out.

The story is a mix of The Andromeda Strain, The X-Files, and more particularly Stephen King's The Stand and The Mist. From Strain the team took the general setting of a superficially impressive government laboratory that turns out to be a poorly-designed deathtrap; from The X-Files they took an overarching conspiracy masterminded by a mysterious and possibly supernatural man in a suit, and from The Mist they took the idea of a group of survivors being menaced by a strange menagerie of alien beasts.

One thing they didn't take from The Mist was the actual mist; the use of fog to limit draw distance was a cliché of early 3D games and thankfully Half-Life uses clever level design instead.

There's a theme running through Stephen King's books. In times of peril, human beings will band together into groups, but instead of fighting the real enemy they will turn on each other; at the same time King's fiction isn't unremittingly dark and cynical. There is good and evil in his universe, but good never has it easy. Half-Life has something of King's work about it, with the result that some of the game's most memorable sequences involve the player fighting against other human beings, or observing while two groups of baddies fight amongst themselves.

Eventually the game takes this idea too far - the player has to fight a second bunch of soldiers who have been sent to wipe out the first bunch, after which a mysterious agent apparently blows up the first and second group of troops with a nuclear bomb. Half-Life's simple but effective story is a model of simplicity but the plot doesn't hold up to close scrutiny.

Still, at least it has a plot. Half-Life's contemporaries either had terse mission briefings, or vastly overwritten cutscenes with piles of meaningless backstory. Half-Life was a taut thriller in a world of soap operas.

I haven't explained the plot. The game has a plot. You are Dr Gordon Freeman, superfit twenty-something MIT graduate. You are an expert on particles. You can name all of them. You have recently started work at Black Mesa, an enormous subterranean laboratory in the New Mexico desert. Your coworkers are jerks! They're mean to you all the time. Your knowledge of particles is useless because they only ask you to push buttons.

Freeman is obviously supposed to be the typical PC gaming fan circa 1998. He is wish-fulfilment for early-twentysomething graduates circa 1998 who had just started working for UBS Warburg or IBM. Freeman's co-workers are older than him; they may know more about experimental physics, but can they swing a crowbar hard enough to smash a wooden crate into fragments? Can they operate a homing rocket launcher? Are they bulletproof and immune to pain? No, no, and no and no in that order. Old people suck.

Eventually there is an accident in the lab and there is an explosion and alien monsters start flooding the place and most of the old people die and Gordon Freeman has to escape, which he does, although the military try to kill him; and then he is asked to go to the alien homeworld, at which point the game turns into a really bad platform game. Let us not talk of Half-Life's last few levels, in which the player has to make a series of difficult jumps in low gravity while being shot at by an endless swarm of tiny distant baddies who move around quickly. Instead, let us celebrate the things it gets right.

Half-Life was notable for a number of things. At the time it felt as if the designers had stripped the first-person shooter down to its components, polished all the parts, and then rebuilt it, adding some new ideas along the way. On a visual level it had a clean, effective, relatively low-key design that could best be described as transparent. It didn't have the visual flash of Unreal, but it was effective at getting across the atmosphere of a ruined science lab. The engine handled claustrophobic vents and large interior spaces equally well, only really falling down when Gordon went outdoors. The alien environments in the final section were abstract enough that the limited polygon count wasn't too obvious. Half-Life also stood out for its seamless storytelling process whereby the game was never interrupted by animated cutscenes. Instead, all of the conversations and mission briefings were scripted as part of the game itself.

The non-player characters had primitive skeletal animation, which was a big thing at the time. Most of the advertisements mention it, although nowadays it is so common that people tend to remember the action setpieces instead. Half-Life's gameplay was essentially a series of action puzzles split up with generic corridor shooting, but the firefights were broken up with quiet sequences that made the eventual explosions of action seem more intense. The game was praised for the clever AI of the enemy soldiers, who threw grenades to flush out the player and tried to flank him. The developers used a trick to do this - enemy soldiers only appear in enclosed arenas and their movements are heavily scripted - but it was undeniably effective and felt light-years ahead of anything else.

The game also had a mass of little touches that worked on an almost subliminal level. It did away with obvious loading screens by masking the level transitions with elevator rides, one-way plunges into darkness, teleporters and so forth. The relatively realistic offices and laboratories meant that the alien monsters seemed even more strange; the abstract sci-fi setting of Quake 2 felt unimaginative in comparison.

I say relatively realistic; the game asks us to accept that Gordon Freeman's workplace contains a military helicopter base, a satellite launch pad, and a hydroelectric dam. Half-Life was released during the dot.com boom, at a time when it was reasonable to suppose that Enron and Cisco might become major world powers, with their own space programmes. Almost two decades later it is much harder to believe in the gigantic invincibility of the commercial sector.

The game's acting is still really, really good, mindbogglingly so compared to the competition in 2004.

Gordon can carry an entire platoon's worth of weapons at once. Perhaps his suit has a special pouch. The first few weapons are drawn from reality. The ray guns and alien insect shooters that appear later in the game feel even more unusual because the player has, until that point, been equipped with recognisable copies of a Glock 17 and a HK MP5 submachinegun. For the first time that I remember in a first-person shooter the firearms could be reloaded manually, and so the player had to account for magazine changes during gunfights. Furthermore the player could take a short break during the quiet sections to reload his arsenal. It sounds trivial, but at the time it felt like a computer game version of the "lock and load" montage from action films.

Half-Life was one of the first games to use Creative Labs' EAX, which gave the concrete hallways and metal sludge tanks natural reverb. The gunfire sounds were mixed loud, and the sound design was such that the game alternated moments of ear-splitting explosions with quiet tension, just footsteps and the occasional crunch as the player stepped on a roach. At the time most other games were a non-stop cacophony of nu-metal and laser blasts. In contrast Half-Life's musical soundtrack felt like an afterthought; it streams from CD periodically, which made my game pause back in 1998 so I turned it off. I don't remember any of it.

The game suffered from a relative lack of replayability. The setpieces and storyline were heavily scripted, and so although the fights were still fun, a lot of the game felt like an illustrated novel on a second playthrough. Some elements just didn't work. The developers were inexplicably fond of jumping puzzles. This became particularly frustrating in the final levels, which were set in an alien dimension with low gravity and slippy-slidey floors. Amiga Power mocked slippy-slidey floors in the early 1990s and their concerns were no less valid in 1998. If the magazine had been around in 1998 it would have mocked Half-Life's jumping puzzles. I miss Amiga Power. It had balls, and guts, brains, a liver, eyes, a soul.

Skin, bone and so on. The emphasis on an engaging single-player game was unusual at the time. In 1998 the future of the first-person shooter was multiplayer-only; the big action games of 1999 were Quake III Arena and Unreal Tournament, which had perfunctory single-player modes that involved fighting bots. They were hugely popular and Unreal at least still has a following, but in the late 1990s it seemed that they might totally displace single-player games, which of course did not happen. Half-Life breathed new life into single-player first-person shooters and demonstrated that there was room in the world for the two flavours to co-exist.

Half-Life was followed by a pair of budget-priced mission pack sequels, Opposing Force and Blue Shift, that were about two-thirds the length of the original. They were developed by Gearbox Software, infamous nowadays for the back-to-back catastrophes of Duke Nukem Forever and Aliens: Colonial Marines. Opposing Force was their first product, and contrary to the team's recent track record it was pretty good. It took the gameplay in a more overtly military direction, with some new weapons and a new bunch of aliens. This player this time controlled a soldier - a good soldier, not one of the evil soldiers from Half-Life.

The idea of nested government conspiracies is one of the things that dates Half-Life to the pre-9/11 period. It was a time when jaded Generation Xers lapped up conspiracy theories involving the United Nations and FEMA, and the US government was often portrayed in fiction as the evil stooge of a higher power. In the original game Gordon slaughters dozens of actual US Marines, who are portrayed as illiterate jocks. They taunt the player with graffiti that reads "YORE DEAD FREEMAN". They aren't impostors dressed as Marines, or brainwashed zombies, they're actual US soliders, whereas the sequel, released two years after 9/11 in a different political climate, makes a clear distinction between the US army and the game's human opponents. I'm digressing. Opposing Force was a legitimately inventive sequel that has been sadly neglected by subsequent canon; Blue Shift on the other hand was a barrel-scraping exercise that compiled an add-on developed for the game's cancelled Dreamcast port with a controversial high-definition texture pack that improved some of the details but changed some of the weapon models for no real reason,

The two Half-Life games are completely different on a tonal level. Half-Life has a cynical, spoofy tone. The deaths of NPCs are treated as slapstick, and the soldiers are parodies of the drill sergeant from Full Metal Jacket. It was a product of the age of irony, but mid-way between 1998 and 2004 irony died, if only temporarily, and Half-Life 2 wears its heart on its sleeve. The player is supposed to care about the other characters; there is good and bad. The characters of Half-Life 2 are not bored of life. They genuinely believe that the future will be better, and that it is worth fighting for.

I still have my original Half-Life CD-ROM. It still works. Everybody had Half-Life. It sold millions. The game is nowadays available on Valve software's Steam gaming platform. There are two versions; the original, and Half-Life: Source, which ported the content to Valve's modern Source engine. Sadly the developers didn't take the opportunity to add anything of significance, and about the only thing going for Half-Life: Source is the ability for the player to start a new game at a certain chapter, rather than from the beginning.

Eighteen years later Half-Life is exceptionally well-documented and after spending a while browsing through the Half-Life wiki I am astonished that Valve got the game out in just two years. The abortive first version looks absolutely dire. You could probably make a new game out of the elements that were cut from Half-Life; it would be the tale of a surly, bearded scientist called Ivan who has to battle stukabats, panthereyes, and hostile security guards. Today it would be remembered as fondly as Klingon Honor Guard or Requiem: Avenging Angel, e.g. it would not be remembered, fondly or otherwise.

The original design was strictly a player-vs-the-entire world affair, but after messing with the AI the developers decided to make some of the NPCs helpful, particularly the security guards. In the finished game the guards are really just walking meat turrets, but the voice acting was surprisingly charming, and in the expansion packs the NPCs developed a life of their own. The guards were dubbed "Barneys" by the gaming press - after Barney Fife from US television's The Andy Griffith Show - but over time Barney, singular, became a character in his own right. Given that Gordon Freeman never speaks throughout the series Barney became the nearest thing to the player's internal voice in Half-Life 2.

Barney is one of the best-loved characters in the series. I have a suspicion that if the story had been completed Barney would have survived to have a happy ending. On a dramatic level Freeman comes across as the perpetually-unsatisfied loner character that appears in The Searchers, Dirty Harry and so forth, the kind that is never satisfied and can never settle down. I mention up the page that Half-Life appeared without fanfare. There were demos and publicity videos, but my recollection of 1998 is that everybody was excited about Unreal and whatever Id was going to do after Quake II. I don't remember reading a single thing about Half-Life before its release. Console fans probably don't remember it at all because it was never ported for the Playstation or N64.

Half-Life's history as a console game is not a distinguished one. The original title skipped the Playstation and was instead ported to the Sega Dreamcast and Playstation 2, although the almost-complete Dreamcast port was never officially released. A port for pre-OSX Macintoshes had a similar fate. The Playstation 2 port improved the graphics and added a mission pack, Half-Life: Decay, but by late 2001 the game was showing its age. Half-Life 2 coincided with the Playstation 3 era. The distant, pre-2008 period when people were prepared to pay five hundred and ninety-nine US dollars for a games console.

The PS3 was notoriously difficult to develop for, and Gabe Newell publicly slammed the console; the port was released as part of the Orange Box compilation and although it was surprisingly faithful the later levels suffered from a choppy frame rate. The Xbox port was apparently a very good translation of the game, although I imagine no-one played it given the original Xbox's poor sales. From the 2010s onwards essentially any modern gaming platform has been able to play Half-Life 2 satisfactorily. As of this writing the Orange Box compilation is available on the Xbox store for the Xbox 360, although it will also work on the Xbox One. The Playstation 3 version of the game is only available on the used market.

Both Half-Life games are of course available for PC gamers on Valve's own Steam delivery platform; Half-Life 2 was also released as a boxed product, although you need Steam to make it work. Surprisingly, Half-Life 2 was also ported to the video arcade, as Half-Life: Survivor. It was released in Japan, and only in Japan, in 2006. Judging by the videos I have seen on Youtube Survivor manages to include most of the original game, with some editing that tightens up the storyline. The second half of "Route Kanal" is cut, and after completing the first half of "Water Hazard" the player goes straight to Ravenholm; the driving section is cut in its entirety.

Did I mention Raising the Bar? It was a coffee table book released by Valve in 2004. The title was a pun - Gordon Freeman's most basic weapon is a crowbar, which he wields to deadly effect against the alien monsters - but the Half-Life games really did elevate PC gaming, if only a little bit. If any other developer had released a book called Raising the Bar they would have been accused of arrogance, but my recollection is that the Half-Life games really were beacons of quality. The odd thing is that despite their strengths, it's hard to pinpoint any lasting influence they had on subsequent games. Half-Life's in-game storytelling was widely praised, but it didn't kill off cutscenes in other games. First-person shooters still force the player to watch bad digital actors deliver an atrocious script that goes on and on and on and on to this day. Half-Life 2 still feels like a one-off. It was preceded, accompanied, and followed by a flood of military and sci-fi shooting games - Call of Duty and Halo, Medal of Honor and Crysis - that owed nothing to it. Has there been a game since Half-Life 2 that combined aggressive action, clever design, an epic setting and recognisably human characterisation? I can't think of one.

That's enough about Half-Life. Let's talk about Half-Life 2. My snap judgement, playing it for the first time in 2012, is that it began well; the characterisation was excellent; it then had a long, fallow period, but picked up; it aimed for a rousing finale and didn't quite get there, but overall the surprisingly warm characterisation and wide range of action environments - ranging from urban to horror to suspense and finally sci-fi, as if the team were showing off their new engine - wide range of action environments I've forgotten how I began this sentence.

Like The Dark Knight Rises, Half-Life 2 is simultaneously too long and not long enough. If the two expansion packs were cut in half, with the first half of Episode One grafted onto the second half of Episode Two, they would make one awesome mission pack. The G-man doesn't fit, the end.

The two games share the same characters, the same universe, some of the same sound effects, even a couple of the musical tracks, but they feel completely different. Not once did I believe that Half-Life 2 was a continuation of the original game. It's the tone. If Half-Life is The Rock or Tomorrow Never Dies, the sequel is a modern action thriller along the lines of The Bourne Identity or Casino Royale. It strives for emotional engagement and tries to be more than just a cheap thrill. In the first game your main goal was to save yourself; the NPCs you met died in droves, and when you were finally asked to sever the alien portal the threat to humanity felt very abstract. You were cut off from ordinary people, lost in a world of men in uniform. In the second game however you are repeatedly called upon to rescue your friends, and you see first-hand the result of the alien occupation on civilians. The deaths of NPCs is brutally sudden and the game doesn't treat it as a joke.

The game's story is told in fragments. Much of its impact is lost today because we're all familiar with the basic outline of the plot, but on a first playthrough the effect is bewildering. It's fascinating to read forum posts from people back in 2004 who had finished the game when it was new. "There's going to be a Half-Life 3, that much is a given."

The game begins with Gordon Freeman being magically put on a train to City 17, which appears to be in Eastern Europe. An opening monologue from the mysterious G-man alludes to a great and unavoidable catastrophe, at which point Freeman finds himself on his own in what amounts to a refugee processing centre. Gorden is helped by a mysterious friend, and ends up having an emotional reunion with his former colleagues at the Black Mesa Research Facility.

It was this sequence that made me fall in love with Half-Life 2. The game treats it as a grand reunion of old pals, but in reality the player has met none of the characters before. Scientists Isaac Kleiner and Eli Vance were generic NPCs in the first game, and although Barney appeared in the Blue Shift expansion pack he was still just a name and a texture. Nonetheless the scene feels completely natural. The dialogue is warm and engaging, and if the player gets bored of listening to his friends waffle on about teleportation the laboratory itself has some props to play with. It's interesting to compare it with the same scene in one of the early betas, in which the characters are assholes (except Barney, who is a moron) and the dialogue is boring and there's too much of it:

The lab helps to introduce the game's particular look. The Earth has been conquered by a mysterious alien force, The Combine, who have obliterated much of humanity and are busily draining the planet of its natural resources. As a consequence the human resistance has to make do with what it can liberate from the trash, and Kleiner's lab has a mixture of futuristic teleportation technology and old-fashioned CRT monitors and dot matrix printers. The blend of styles continues throughout the game. The weapons are a mixture of real-world designs and plausible alien modifications of existing technology.

The Combine are portrayed as a parasitic race that absorbs, blends, and regurgitates the knowledge of its foes. Throughout the game Gordon Freeman encounters APCs and body armour that look like real designs but are a bit off; Kevlar body padding and velcro straps mixed with with bright red monoculars, vehicles that seem to be made of a single piece of painted iron. The alien flying machines resemble giant insects crossed with rubbish skips, perhaps based on technology stolen from other unfortunate Combine victims.

It struck me after a while that the CRT monitors and dot matrix printers are out of place. Even in 2004 they were obsolete, and the game is set twenty years in the future, by which time they will be extremely rare antiques. It's possible that the designers felt that CRTs would still be common in Eastern Europe, but I like to think that Half-Life 2 takes place in the same universe as Terry Gilliam's Brazil, "somewhere in the early 21st Century".

The game's opening sequences also introduce another entirely new character, Alyx Vance, a young woman who accompanies Gordon throughout most of the rest of the story. In any other game she would have been a teenage latex-clad kickboxing ninja assassin in a schoolgirl uniform. She would tearfully reveal to the player that she acts like a hussy because her parents were mean, and she would fire teddy bears at the enemy. She would have latent psychic powers. Her armour would consist entirely of a pair of leather straps that criss-cross her chest. Gordon would be able to manipulate her breasts with his gravity gun. In any other game.

In Half-Life 2 she is an ordinary human being. Thin and lovely but not overtly sexualised. She wears a sports bra. She is neither an emotional wreck nor a sex-crazed killing machine. The developers wrote her as a young girl who has had a horrible life but has come through intact. She shows realistic concern for the fate of her father, who at one point is kidnapped by the baddies; her relationship with Gordon Freeman is warm with a hint of distance, as if she was used to seeing all her friends killed in front her, but all of this is conveyed with clever writing rather than emotional outbursts.

Overall the characterisation in Half-Life 2 is an enormous step up from the first game, and from most other games, and furthermore it feels natural. Other games have pages of dialogue to no effect, or characters with backstories that could fill a book, again to no effect; Half-Life 2 has a few lines of dialogue and suddenly I know Barney Calhoun, I could imagine having a beer with him.

BOXOUT: Let's Get Physical (Physical)
Half Life 2's earliest tech demos touted the game's AI and its advanced physics engine. YouTube has a recording of the game's presentation at E3; the demonstration shows bodies flying through the air and piles of objects exploding into realistic clouds of debris. It also exaggerates the game's AI, but that's another topic entirely.

Back in 2004 realistic physics modelling was right on the cutting edge of computer games design, and Half-Life 2 attracted a lot of press because of it. The game's most memorable weapon is the zero-point energy manipulator - Gravity Gun for short - that can pick up objects and throw them around. Some parts of the game are designed so that you can play them exclusively with the gravity gun; Ravenholm in particular is full of sawblades and exploding barrels that you can use to bisect the zombies and set them on fire.

Physics-based gameplay has been around since the dawn of gaming. The very first versions of Lunar Lander were written for PDP-8 minicomputers in the late 1960s; they were inspired by the contemporary Apollo project. In Lunar Lander the player has to guide a space capsule to a soft landing on the Moon without running out of fuel or hitting the surface too fast. Although the game was originally text-based most people today are familiar with Atari's 1979 arcade version. Lunar Lander flourished and faded because the concept was limited, and much the same thing happened to physics-based games in the mid-2000s.

Physics gameplay was pioneered in the modern era by the 1998 Jurassic Park tie-in Trespasser, which was far too ambitious for the technology of 1998 and is nowadays remembered as a noble failure. Trespasser made the player interact with the world using the player character's right arm, which worked like a robot arm and looked just as unnatural. Unfortunately the physics engine was never properly finished, and although the developers promised a game that would have physics-based puzzles, most of the gameplay was cut out or reduced to making the player jump on piles of boxes that had already been stacked for you. Half-Life 2 did away with the robot arm (when Gordon picks things up they just float in front of him) and mostly debugged the physics. Early in the game Gordon has to stack objects onto a see-saw so he can make a high jump, which is a tediously obvious idea that gave physics-based games a bad reputation; but it's an aberration, and for the most part the physics puzzles are optional. They re-appear in a later level called Sandtraps, in which you have to navigate a beach without stepping on the sand. Gordon has to shift pieces of wood around. It's boring.

Ultimately developers realised that there was only so much gameplay in stacking and/or throwing objects, and purely physics-based gameplay fell by the wayside almost as quickly as it emerged. Portal and Kerbal Space Programme took the idea in an interesting direction but on the whole modern games no longer make realistic physics a selling point. It is just one of many weapons in a games designer's arsenal of cookery ingredients.

Physics!

We learn very little of what happened when The Combine came to Earth. Our defence wasn't very effective, and now the remaining urban centres are full of junk and broken cars, smashed bridges and collapsed buildings. In a propaganda broadcast the villainous Dr Breen imagines a future in which humankind's legacy is "fated to be nothing more than a layer of broken plastic shards thinly strewn across a fossil bed, sandwiched between the Burgess shale and an eon's worth of mud", although his proposed alternative is hopelessly vague. In Breen's future, humanity will be immortalised not as a living entity, but as a compressed archive in a transdimensional data warehouse.

A couple of years after I first played Half-Life 2 there was a revolution in Ukraine, and the scenes on the television news of riot police and snipers facing protesters amongst the rubble of a modern city were uncannily reminiscent of the game. It sounds ridiculous, and I don't want to trivialise actual human suffering, but I'm not the only person to notice this.

Its development predated the invasion of Iraq - the urban combat stages were probably inspired by footage from the Yugoslav wars, or perhaps the film of Black Hawk Down, from a different century - but nonetheless there are uncanny parallels with Mosul and Fallujah in some of the game's later stages. The game was even used as the basis for an Iraq-themed tactical shooter, Insurgency, which was released in 2007 and then re-released in modified form in 2014.

In this example of physics-based gameplay I have surrounded a man with furniture. I am standing on his head.

I've skipped over the game's development. In brief, Valve worked on the game during 1999-2003 and ended up with a large and unwieldy mass of ideas. The game originally had a tonne of extra weapons and monsters, and almost twice as many maps. Most of these elements were built into a workable state, and several mods have tried to reintroduce the cut content, but the problem of polishing so many things into greatness was too much for the team. Valve eventually decided to remove large chunks of the storyline, notably chopping out a large sequence involving an Arctic research ship called the Borealis, so that they could concentrate on improving the bits that remained. In 2003 a release date was announced for later in the year, and a presentation at the 2003 E3 was very popular.

At that point most of the game's content was leaked to the internet by a cracker; the leak revealed to one and all that the game still needed a lot more work. It's a testament to how unfinished the game was that the leak didn't ruin the storyline. Doubts were raised about the veracity of the E3 demo; despite the narrator's boasts that the move-and-cover behaviour of the characters was unscripted, it's odd that this doesn't appear in the final game. It appears that the demo used scripted behaviours in order to emulate AI routines that Valve couldn't get right, which felt underhand.

The final year was spent bringing the game up to scratch, and after release in late 2004 the team continued to work on the technology. A 2005 mini-level, Lost Coast, introduced a new HDR technology that simulated the human vision system's response to changes in light levels; this was backported to some levels in the original game.

Contemporary professional reviews were uniformly positive. Edge gave it a rare 10/10. This review, at FourFatChicks, is interesting for its glimpse of how scanty the storyline must have seemed in 2004. In my opinion Half-Life 2 could have done with a little bit more work - the opening sequences are too long, the middle digresses too much, the ending is too short - but nonetheless the developers did one hell of a job given that they had to build a graphics engine, integrate a physics engine, develop the game, and also develop Steam.

What is Steam? Steam is one of the reasons why I avoided the game in 2004. It's Valve Software's digital games delivery platform. Digital delivery had a mixed reception in 2004, especially given that people still used dial-up. Half-Life 2 was available as a boxed product, but you had to install Steam and unlock the game over the internet before you could play it. Nowadays this is not unusual, and Steam has a huge library of games, but in 2004 it seemed a lot of bother. The other reasons I didn't buy the game? When Episode One came out I felt that I would be missing something if I didn't buy the original as well, but this would double the cost; when The Orange Box came out the likes of Team Fortress and Portal - obviously a throwaway novelty - didn't appeal to me, and beyond that Half-Life 2 was old-hat. Why did I buy it in 2012? Fate called to me. She has a plan for me. People reading this in the future will know what fate had in store for me; I will no longer be here.

Half-Life 2's opening level illustrates the games strengths and weaknesses equally well. It's called "Route Kanal". You are given a crowbar and a protective environment suit and told to make haste to the rebel base. What follows is a hectic chase as Gordon flees through a set of canals and sewers.

The level acts as a tutorial, with a couple of simple physics problems and some easy combat. It introduces some of the enemies and part of Gordon's new arsenal, but although the strange new environment and shooting sequences are initially intriguing, it goes on too long. It's followed by another lengthy chase in which Gordon drives an airboat down another set of canals.

The novelty of driving a vehicle is interesting for a short while, but even contemporary reviewers pointed out that the opening sequence could have done with a bit of tightening. If the game had a non-linear map whereby Gordon could journey back and forth between rebel outposts (say), the canal sequence might have been more effective, but Half-Life 2 is a thoroughly linear experience. It was designed to wow the first-time player, the first time he or she played it; but as with the original the scripted enemies and scripted action sequence have very little replay value.

Frustratingly, the developers cracked this problem with the final battle of Episode Two, which is fun even the second time, but alas that was the end of the show, there was no more. Just as they had finally warmed up, they stopped.

Some things date the game to the Silver Age of First-Person Shooters. The weapons look realistic, but with the exception of the sniping crossbow Gordon never uses the sights; the damage model is such that Gordon is expected to constantly gobble up health kits. The AI in the second game is a mixed bag. Behind the scenes it is apparently very clever, and there are sequences in the expansion packs that show it off, but the scripted encounters and tight corridors of Half-Life 2 box the enemy in. The baddies generally just charge at Gordon.

In the opening levels Gordon faces a bunch of jumped-up paramilitary goons who are absolutely terrible at combat. We have to assume they didn't expect anybody to fight back. They spend most of their time bullying defenceless citizens with their stun batons, and when Gordon finally snaps and fights back it's an emotionally satisfying moment.

At least, it's emotionally satisfying until you think about in greater detail. Former Black Mesa security guard and current resistance hero Barney Calhoun is shown to be working as a Civil Protection officer - during the opening sequence he arranges for Gordon to be delivered to his interrogation room, and then sets him free - which implies that the rest of the Civil Protection policemen are ordinary human beings doing perhaps the only job left available to them. Gordon kills dozens of them. In fact throughout the game almost the only enemies he fights are human beings, which are in the game's world a finite resource. Gordon never meets a Combine occupier; one appears briefly towards the end of the game, and a couple appear in the sequels, but they paralyse Gordon telekinetically before he has a chance to whack them with his crowbar.

Instead of fighting their wars directly The Combine make their conquered peoples fight each other. The parallels with Nazi collaborators are explicit and obvious; the Civil Protection Metrocops are reminiscent of Lacombe, Lucien; the villainous Dr Breen is a mixture of Vidkun Quisling and perhaps Philippe Petain. The game shows us that the price of collaboration is awful, which brings us to one of the game's great strengths, its verisimilitude. The air of reality; the sense that this is actually happening.

Half-Life 2 was released at a time when almost all computer games were pumped up with enormous weapons, muscle-bound heroes, pneumatic women and so forth; when Half-Life 2 goes for spectacle it does so sparingly, and only within the context of the story. It aims for an approximation of our world rather than outright fantasy. The uniforms worn by the security forces have a futuristic eyepiece but are otherwise reminiscent of modern-day body armour. Gordon's environment suit can listen in on Civil Protection's radio chatter, which sounds like modern-day police dispatcher radio noise. The CP radios flatline when they die, an eerie touch.

BOXOUT: Blah-blah-blah, Mr Freeman
Early in the first game Gordon spots a chap in an office. A man in a suit, with a smart briefcase. In fact he appears even earlier in the game, during the opening cinematic...

Half-Life's opening sequence is justly famous; Gordon takes a train ride to work on a monorail that travels through the expansive Black Mesa research facility, and although nothing happens the combination of a calm computer voice reading out safety regulations and the occasional glimpses of dangerous work practices from the monorail foreshadow the disaster that follows. The cinematic was also notable for being generated with the game's engine, rather than being a video file played back from the CD-ROM. In 1998 the possibilities seemed endless.

... early in the first game Gordon spots a chap in an office. In fact he appears even earlier in the game, during the opening cinematic, and throughout the two games he pops up in unexpected places, always off in the distance where Gordon can't reach. He disappears into thin air before you get there.

In his first substantive appearance he is engaged in heated discussion with one of Black Mesa's scientists, their words inaudible. The mysterious chap in a suit goes unnamed, although fans quickly dubbed him the G-Man for his resemblance to a stereotypical FBI agent (and for that matter the Cigarette-Smoking Man from television's The X-Files).

The G-man is problematic. He was presumably dreamed up for Half-Life as a throwaway character; on a narrative level he's superfluous, but he gives what would otherwise be a prosaic action-disaster spectacle an air of mystery. At the end of Half-Life he appears in front of Gordon Freeman and offers him a job as an interdimensional troubleshooter, leaving the way open for sequels. The problem is that the developers don't seem to have thought very hard about his role. As an all-powerful supernatural being, why does he need Gordon? Plot-wise he engineers the disaster at Black Mesa so that Gordon Freeman has an excuse to shift dimensions and kill the gigantic Nihilanth, but given that the final sequences show wrecked tanks and military equivalent, and given that the Nihilianth is not immune to ordinary bullets, why bother with Gordon? Why not just send the military there directly? If the whole thing was a giant job interview designed to pick Earth's most effective alien troubleshooter, why create a disaster that killed off almost all of Black Mesa's scientists? What if one of them was smarter than Gordon?

The G-man is even more problematic in Half-Life 2. As with modern-day attempts to rework Superman, Batman and the like, the writers of Half-Life 2 struggled with the task of translating a load of pulpy nonsense into a quasi-realistic framework. To their credit Half-Life 2 mostly works, but even though the G-man is essential to the plot he feels out of place. He is able to freeze time and bring people back from the dead but he still needs Gordon to blow things up; if his mission was of any importance why not recruit hundreds of helpers, rather than just Gordon? Why recruit a doctor in theoretical physics instead of a charismatic public figure such as Donald Trump? How come Gordon is a folk hero in the second game when he was just a nobody in the first game?

Half-Life 2 implies that the G-man has some kind of telepathic hold over the minds of Gordon's former colleagues. It's never clear whether he exists for the other characters in the game. A couple of characters allude to his presence, but in a dream-like context, as if they were vessels for his thoughts. No-one seriously cares that Freeman hasn't aged in twenty years - his former colleague Eli Vance mentions it as small talk - so presumably the G-man has clouded the minds of everyone Gordon meets. The G-man character is a mess, but without him the game would seem flatter and more ordinary.

Mid-way through the story we learn that the soldiers and super-soldiers who fight Gordon have undergone surgical modification. In another game they would be eight-foot-tall steroidal juggernauts; in Half-Life 2 the altered soldiers are pale, weak, scrawny men with plugs in their throats and stomachs where the food goes in and comes out. They resemble cancer victims.

Later in the game we see human beings who have undergone even more radical alterations in order to operate the Combine's machines; the "stalkers" have withered, emaciated torsos. Their hands, feet, and genitals have been removed. They are used by The Combine as technicians, and there is an implication that the remainder of humanity is being kept alive merely as a source of spare bodies.

Half-Life 2 has an undercurrent of melancholy, but the transhuman nightmares of the Combine's devising are downright unnerving. If this is the future of humanity we are better off dead. The stalkers are a background detail, although they feature in one of the most memorable character moments in the series; in Episode One Alyx is brought to the verge of tears by a panicked stalker, not out of fear but out of pity. We never see The Combine directly attack humanity, but we see enough of their handiwork to want them wiped from the face of the Earth, if not the entire universe, never to return.

I love the word verisimilitude so much I want to snort it like cocaine. Half-Life 2's cityscapes are a distinctive mixture of mitteleuropean classical buildings with alien embellishments; The Combine has grafted its metallic architecture onto what could be Budapest or Riga. The Combine's buildings construct themselves. They expand outwards and reconfigure like Dark City, and on several occasions Gordon is menaced by shifting architecture.

In my opinion The Combine must have absorbed top late-1990s British design bureau The Designers' Republic early in their attack. They liked what they saw, because the alien designs have something of a late-1990s Warp Records album cover about them; Half-Life 2 has an unusually consistent design language courtesy of art director Viktor Antonov, who was given carte blanche to indulge himself.

The initial design ideas for Half-Life 2 depict a clichéd night-time steampunk hellscape that would have probably resembled Deus Ex, but for the finished product the designers gave everything a cool European look. The game even feels European; little things, such as the use of train travel as a recurring motif, or the cowed population, or the authoritarian Combine regime are quintessentially Continental.

Gordon Freeman is of course American; if he had been from France or Germany Half-Life 2 would probably have ended with Freeman personally apologising to the Combine for being a small-minded nationalist, whilst secretly cutting a deal whereby he is given a lucrative job as Secretary-General of one of the Combine's many bureaucracies. Being American Gordon of course fights back against the Combine's oppressive government, albeit that he destroys everything around him - including City 17 itself, which is obliterated in an antimatter explosion, presumably killing hundreds of thousands of survivors who were just minding their own business. In the world of Half-Life 2 humanity has a choice between liberty or death, with the complication that death is preferable to the Combine's long-term plan to turn human beings into zombies or surgically-altered freaks.

Half-Life 2 has aged well on a technological-visual level. The Civil Protection police make use of razor-sharp drones, Manhacks, that they carry on their person and deploy when necessary. When the game was being developed few people outside of the military had heard of drones. The idea of consumers owning a drone of their own was still science fiction, but within a year of the game's release drones had become a ubiquitous component of modern Western warfare, and a few years later they were a hot new Christmas toy.

Half-Life 2 wasn't intended as a serious work of speculative fiction, but thanks to the intelligent design and a restricted environment nothing about the game has really dated. As with the CRT monitors, the Combine's iron machines and oversized computer consoles seem to be a deliberately anachronistic blend of technological ideas plucked from the Victorian and late-modern eras; there is an implication that although the Combine are very successful, they are also grossly inefficient, like a space-age variation of Soviet industry. This would explain their voracious need to drain entire planets of their resources, and it might also explain why the mysterious G-man wants Gordon to get rid of them; in the long term they will leave behind a dead universe filled with dead planets.

The game doesn't even make the common mistake whereby people in the future still use PDAs, with mobile phones purely for voice calls. The strange afterlife of PDAs in computer games is a testament to the lack of genuine imagination in the games industry; it reminds me of old science fiction stories where there are intelligent robots who act like human beings, but spaceships are piloted by giant computers that communicate with ticker-tape. There's a sad lack of imagination in science fiction, fantasy, and computer games. It comes about because creative types in those industries just copy the things that came before, without considering how they came to be. You have to know where things came from before you can work out why they exist and where they are going.

I'm digressing again. Combine machinery has QR codes and logos that look as if they might make sense; the broken rubbish that litters the streets includes recognisable modern-day chairs, washing machines, buckets and so forth. The sudden appearance of Combine machinery - brutally grafted into its surroundings with no attempt to make it blend in - is made even more jarring by the contrast with its mundane surroundings. Throughout the game The Combine uses medical language to describe the human infestation, but they are a kind of metal cancer themselves.

Back in 2004 the game's graphics had a muted reception, overshadowed by Doom 3, but as mentioned earlier the game has style. Half-Life 2's contemporary Far Cry and 2007's Crysis attracted rave reviews for their detailed graphics but they didn't have a distinctive visual style. The problem is that the novelty of realistic foliage and visual effects wears off, at which point the underlying game is laid bare, and Crysis didn't have much to offer in that respect.

The same thing happens to every game that relies on overwhelming visuals for its impact. It happened to Atari's Battlezone, the arcade laserdisc title Dragon's Lair, the original Doom, Unreal; as in real life, good looks get you through the door, but you get used to good looks, and then you realise that your ex-wife was in fact an evil liar who spent far too much of your money on hair-care products and refused to remove all those empty bottles from the shower even though they were empty. Half-Life 2 has a rough day-night-day-dusk cycle, and the designers made the bold decision to begin the game in bright, blinding sunlight as opposed to the night-time murk of Deus Ex. Instead of hiding the monsters in shadow, the game's first glimpse of the repulsive alien tentacle monsters is in a well-lit, realistically grimy sewer.

I mentioned the game's undercurrent of melancholy. Gordon Freeman scores a series of minor victories against the police and light infantry forces occupying City 17, but the game implies that The Combine don't throw their whole weight against him. Their resources are limitless and eventual human victory seems extremely unlikely. Furthermore even if Gordon beats the Combine, the Earth has been thoroughly poisoned. Most of the countryside is infested with poisonous aliens and oversized bugs, and even the sea level is much lower than it should be. This suggests that billions, probably trillions of tonnes of seawater have been siphoned off-world, causing incalculable damage to the Earth's biosphere. Antarctica must now resemble a huge mountain. Half-Life 2 presents an alien invasion that has given humanity a mortal blow; short of a miracle, humanity is doomed, and the best Gordon can do is give us time to erect a monument to ourselves.

Amongst the Combine's arsenal of weapons are headcrabs that latch onto their victims' face and gradually merge with their body, turning the host into a hostile zombie. The zombies of Half-Life were among the game's few overly horrific elements, and they are even more horrible in the sequel. One level set in the deserted town of Ravenholm is outright Grand Guignol, a night-time level that also serves to teach the player how to use the physics-based gravity gun.

Ravenholm is essentially an interlude - it feels like a dream - and although the shock wears off it is at first genuinely unnerving. You can set the zombified human beings on fire, at which point they shriek in pain and fear; they are voice-acted as if they were living people with a malevolent pillow over their heads. Their rotten bodies burst open with a wet splutch. Playing through Ravenholm I was again reminded of the fact that Gordon spends the entire game killing other human beings. As part of the game's backstory, The Combine has blanketed the world in an energy field that stops people from conceiving children; there is an implication that it suppresses sexual desire as well. Behind the scenes, the developers planned to have child slaves in the game but decided that it would be macabre. One of the first locations has a deserted playground, and if the player loiters there the environmental audio plays the sound of children playing. Again, this is something that is delivered subtly in the game, and you might miss it; I know about it because I've read about it on the internet.

The environmental audio deserves special mention. The design is complemented by a subtle sonic ambiance. There are some clever technical tricks - distant explosions detonate with a muffled whump, and the sound reaches the player with a noticeable delay - but beyond that the background noise is lovely without being oppressive; the coastal road has some lovely howling wind noises. City 17 in particular has a mixture of city sounds, distant sirens, and official proclamations from the local Overwatch computer, who is voiced as a posh British lady. Here's a short piece I compiled with bits of the game's ambient sounds:

At first the Overwatch voice seems to be delivering generic instructions to the Metrocops - as if the dialogue was generic pre-recorded chatter - but at one clever point it becomes obvious that you are the target. At first are a "miscount", but later on you become Anticitizen One, and it feels good. The Combine think of Gordon as a disease, with the Overwatch ordering her troops to sterilise, cauterise, contain, and amputate the player. Combine soldiers use a context-sensitive battle language that is tied to their AI routines; their radio voices essentially debug their behaviour. In another touch of verisimilitude the processing is exactly like real-life police dispatch radio, and the language is a convincing imitation of tactical military jargon. "Stab Five, ready charges, bouncer bouncer! Ghost drop BI-BLIP inbound target contact dash eight ripcord!" etc. Judging by this video on Youtube there is far more dialogue in the game than the player is likely to encounter.

In the expansion packs The Combine lose control of City 17, and some of their soldiers are infected with the very biological weapons they use against the general population. The resulting zombies soldiers - the "zombines" - still deliver status reports, but slowed-down and interspersed with gasps and sucking noises. "Biotics... overrun... (electronic howl)... sector is (sluuurp) not secure...". It's a grim glimpse of what must have been going through the soldier's mind as his nervous system was being poisoned

The game skirts a fine line between humour and horror; the flailing, shrieking zombies and slurping poison headcrabs are simultaneously gross and, once the shock wears off, almost charismatic. The game isn't completely grim - compared to STALKER: Shadow of Chernobyl the atmosphere is much lighter, and at the same time more diverse - and I assume that the developers wanted it to have a mixture of scares and thrills without one overwhelming the other.

Scares and thrills, and also laughter and sadness, because the game has an emotional core. STALKER is awesomely creepy but emotionally dead; the player is surrounded by unrelenting death and misery, and by the end of that game I felt numb and dead inside. Half-Life may not be Serpico, but compared to the vast majority of video game writing it's almost depressing how good it is.

Most games pad out the cutscenes with masses of plot but no real story; like a bad film, most games are just a series of events that happen one after the other to fill time. Half-Life has a theme, a story. The dialogue is terse, the voice acting is engaging, and although the characters are all stereotypes they aren't annoying. After Gordon escapes the immediate clutches of The Combine he has a breather in an underground lab during which there's a little character bit between the feisty Alyx Vance and unctuous science lady Dr Judith Mossman.

The quality of the writing is such that although Alyx might have come across as a stroppy teenager having a temper tantrum, she instead seems understandably stir crazy. Mossman is more problematic. Almost from the off she is written as an insincere flatterer; and when it seems that she has betrayed the human resistance she comes across as the typical masculinist stereotype of the untrustworthy, traitorous woman who has a independent mind and an agenda and life of her own that might not necessarily require men.

While I have my progressive hat on, Half-Life 2 is on the surface acceptable, but on a deeper level it is a relic of a bygone age. The headcrabs are essentially squidgy, ambulating vaginas that poison men's minds (we only ever see male zombies). In the world of Half-Life 2 women are creepy little biting vaginas that latch on to men, brainwash them, and cause them to become weak and vulnerable. The Combine are portrayed as lazy fat slugs who use psychic powers to pervert their victims, while being incapable of doing anything for themselves; this portrayal of women might have seemed acceptable in 2004, but it is not 2004 any more. On a conscious level the character of Alyx Vance is a positive depiction of how a woman might be just as valid as a man, but on a subconscious level Half-Life 2 exists in a realm where women are still The Other.

Having said all that, it eventually turns out that Mossman's treachery was in fact a ruse. She pretends to be a baddie in order to infiltrate the Combine base, and at the end of the game she saves the day. It's left ambiguous as to whether she was a baddie who changed her mind at the last minute, but at that point in the game the villain has won, and even if Mossman could see a future where The Combine no longer have a need for her, life as a human resistance agent seems far less palatable - and much shorter - than life as a Combine lackey.

I think the clue to her ultimate allegience was in her name, Moss-MAN. From the point of view of the developers she is not wholly evil. Presumably if she had been a villain the woman-hating developers would have called her Moss-WOMAN. I'm digressing here. On a pragmatic level Mossman was probably added to the game so that there were more female characters. She is modelled as a foxy middle-aged woman who wears a form-fitting sweater, and I imagine that some people playing Half-Life 2 in 2004 had elaborate sexual fantasies in which Mossman spoke sternly to them, or perhaps she apologised for being such a naughty girl before begging the player to spank her; or perhaps she offered to let the player wear her sweater and the rest of her woman's clothes.

Half-Life 2 does however satisfy the Bechdel test, albeit only very briefly; the game has two major female characters who have a conversation with each other about something other than a man (in this case a thyristor). The interlude at Black Mesa East also lets us meet Eli Vance, Alyx's father, who is not to put too fine a point on it a coloured gentleman.

In another game he would have been called Eli "Supahfly" Vance and he would wear a powered suit with a huge laser gun, but in this game he is a tired old man with a mechanical leg. He is essentially the Morgan Freeman character, but he is written and voiced well enough that it's not offensive; he has had to watch his daughter grow up in a living hell. We never find out what happened to his wife.

Half-Life 2 reeks of death. If it has a theme, it is the fragility of life; the original game was packed full of disposable NPCs but death carries more emotional weight in the sequel. It's draining. The NPC models are much more realistic and their voice acting isn't played for overt comedy. The bodies we see littered around are often horribly mutilated or burned, and although the game generally has a light touch the corpses are surprisingly graphic. Some of the enemies, particularly the wheezing, bloated poison zombies, are unsettling because there is, or was, a human being underneath that malignant, suppurating mass of virulent pestilence.

BOXOUT: 1998
I don't remember 2004, but I do remember 1998. Half-Life coincided with a couple of interesting trends that seemed very important at the time. History will recall that the Half-Life games were written single-handedly by Gabe Newell, but in reality by 1998 the days of small development teams were long-gone, at least outside the world of mobile gaming, which in those days meant handheld consoles. In the wake of Doom and the Sony Playstation 3D gaming had become ubiquitous, but 3D gaming brought with them a new set of technical challenges.

The big problem is that 2D games were entirely abstract. No-one cared about the physics of Pac-Man, because Pac-Man's world bore no relation to our own; the artificial intelligence of Pac-Man's ghosts was surprisingly sophisticated, but fans of Galaga and the like were happy for the baddies to just fly at the player, shooting wildly. 3D games, on the other hand, demanded at least an approximation of real-world physics, plus sophisticated enemy AI, a well-built engine that could draw large amounts of polygons, preferably some kind of network code, on top of which the level designers had to think in 3D.

Traditionally, computer games can be split into two components; the graphics, sound, and level data, and the technology engine that draws things on the screen and moves objects around. All of this became much more demanding in the 3D era. Each surface had to be covered in an attractive texture; it was not enough to pre-program the characters' movements, they needed some kind of ragdoll or skeletal physics engine; games like Half-Life, Quake, and the original System Shock demonstrated that it was possible to make interesting gameplay out of gravity and inertia, and so on and so forth. 3D games became a giant sucking black hole of resources, culminating in the hundred-million-dollar budgets and vast teams that are common in the modern era.

And so although many of the people who worked on Half-Life became well-known amongst computer games fans, none of them became household names, and the Half-Life series is not associated with one programmer; not in the same way that the Mario games are associated with Shigeru Miyamoto. The Man of 1998 was not a man, it was The Level Designer.

In his right hand The Engine; in his left, a flexible, powerful set of tools that could be use to generate new levels; not just the architecture but the scripting involved in creating action setpieces. Half-Life is remembered as a triumph of level design, and in 1998 the future belonged to level design, not engineering, because someone else was going to build The Engine. In those days there were tales of level designers being hired for handsome salaries for their expertise. In 1996 Id Software snapped up a pair of fan-made Doom levelsets and sold them as Final Doom, a commercial product. This trend culminated in 2001, with American McGee's Alice, a dark and edgy treatment of Alice in Wonderland devised by former Doom and Quake level designer American McGee.

There was also, for a time, a wave of games that had been created purely to show off a new engine, notably Shogo and Serious Sam, and to a lesser extent STALKER: Shadow of Chernobyl. The idea of becoming rich and famous without having to move away from the computer, go outside, or meet other people was powerfully appealing in 1998 but alas just like everything else from that era it didn't take off; the reality of working as a level designer was endless crunch periods and no holidays ever. Nowadays level design itself seems to be a dying art, with top shooters of the modern age being essentially linear tracks with periodic breaks for cutscenes. The ruling powers do not like it when the little men start to have power of their own.

As for The Engine, I suppose that the future came true. Scads of modern games have been developed with Unity and the Unreal Engine; sadly Valve's Source never really took off outside Valve. The Engine doesn't seem bracing and new nowadays because we're used to it. Perhaps one day there will be a single physics-graphics engine that can model reality as well as the real world, plus a level editor that is easy to use and a scripting language that makes sense, at which point there will be no reason to do any more work on it. Or perhaps one day there will be an engine that can model a computer that can run an engine that can model a computer, and the universe will end.

What of 2004? My recollection is that the big game of 2004 was supposed to be Id Software's Doom 3, which came out a few months before Half-Life 2. Ultimately however it was overshadowed both by Half-Life 2 and Far Cry, which had been released even earlier in the year. The three games represented a new era in PC gaming graphics. With the Xbox 360 and Playstation 3 being released in 2005 and 2006 they were among the final generation of visually groundbreaking PC-original titles. Far Cry had a dull story and a peculiar, camp tone, but it begat a successful franchise that continues today. Half-Life 2 is still remembered as a classic.

Doom 3 on the other hand died a death; reviewers loved the detailed graphics, but the game was widely criticised for its uniformly dark lighting scene. There was no story to speak of, and and I remember being disappointed by the gameplay, which was even more simplistic than the original Doom. There was an expansion pack, Resurrection of Evil, which included a physics-based grabber gun that was widely criticised for copying Half-Life 2, although in reality the two weapons had been developed in parallel.

Id then gave up on the Doom franchise for a decade. No-one missed it, although a reboot in 2016 has done well, so I could be wrong.

I've mentioned Ravenholm. Gordon makes a detour through the town, during which he meets Father Grigori, a fantastically overacted priest who shoots zombies with his double gun and chops them to bits with petrol-powered traps. Grigori appears to have come from another game. It's not clear if he belongs to our world or the next. As with all the main characters he is almost invincible and at the end of the level he disappears in a wall of fire. He only appears in Ravenholm and is never mentioned again, despite which he is one of the game's most memorable characters.

Which is more than can be said for Dr Wallace Breen, the chief baddie. He is a former administrator at the Black Mesa Research Facility who has taken it upon himself to be the human face of the Combine's occupation. He calls The Combine "our benefactors", and promises that humanity is on the verge of a great transformation. At one point in the game Gordon stumbles on a television playing one of Dr Breen's propaganda broadcasts; the audience is a burned corpse, the room is a wreck and the street outside is a warzone. It's a clever piece of visual storytelling. Whatever transformation the Combine has in mind for humanity, it probably involves using us as fuel their infernal machines.

The problem with Breen is that his character is played as a bumbling, ineffectual bureaucrat; a comedy villain who berates his underlings for failing to stop the hero from wrecking his plans. He doesn't really work. I suspect that the developers envisaged him as a white-haired variation of Alan Rickman's character in Die Hard, but in the game he comes across as a useless appendix that will presumably be disposed of by the Combine even if Gordon doesn't finish him off. He isn't physically threatening and he only appears in person right at the end of the game, so although we see his face on computer screens and hear his voice, we only meet him very briefly.

Breen does provide one of the game's most interesting visuals. During the uprising against the Combine, Gordon witnesses a group of survivors pull down one of Breen's giant outdoors videoscreens. It was presumably meant as a visual echo of the destruction of Soviet iconography in 1989, but in 2004 it must have reminded people of the toppling of Saddam Hussein's statue in Firdos Square, Baghdad.

The game's emotional arc is simple and effective. At the beginning Gordon Freeman is hunted; during the first few levels he has no time to fight back against The Combine, it is the best he can do to stay alive. Roughly half-way through the story this changes. Gordon has beaten everything the Combine has sent against him, so they kidnap Eli Vance and take him to the notorious Nova Prospekt prison.

Gordon doesn't try to take the prison single-handedly. Instead, he raises an army; and in a left-field design decision the army is made of giant bugs! It's like Lawrence of Arabia, but with giant bugs. Gordon controls them with a pheromone pod, and I could write a couple of paragraphs about the game's parallels with British foreign policy during the days of Empire - a period in which we treated local peoples as if they were, essentially, disposable bugs - but I'm going to save that for my university thesis.

Surprisingly, the bug assault works without feeling silly. The attack on Nova Prospekt is perhaps the game's high point. The initial fight across the beach is exhilarating, because Gordon and his bug friends absolutely obliterate the Combine's forces. The soldiers don't know how to react; they are put on the back foot and the player has no reason to show them mercy. After perhaps the game's most difficult fight Gordon enters Nova Prospekt, and in another clever piece of game design the place is deserted. For the first half of the level Gordon sees fighting in the distance, but never encounters any baddies; the sense of tension is palpable.

The second half of the level is a mixture of bug-assisted close combat, clever physics puzzles, and scripted fights in which Gordon is assisted by robot gun turrets. After a lot of fannying around in boats and cars the game flowers into a rock-hard combat shooter. The rest of the game never really tops the level; the return to City 17, now in the grip of revolution, feels simplistic in comparison, and the final battle inside the Combine's skyscraper is visually stunning but a let-down in gameplay terms.

I mention boats and cars. Contemporary reviews praised the game but expressed reservations about the driving levels. They are concentrated in the first half of the story and are presented almost back-to-back. At first Gordon drives an airboat down a series of similar-looking canals, which quickly becomes boring; and then his boat is given a gun and he has to drive down even more canals. After Gordon finally exits the sewers he passes through Ravenholm, the novelty horror level; then he is put in a dune buggy, and then he has to do a novelty level that involves navigating a beach without walking on the sand.

Players who were expecting a first-person shooter were probably none too pleased with Half-Life 2's first half. The dune buggy level generally works; Gordon doesn't actually drive the buggy all that much, instead he uses it to travel from one action sequence to another, and furthermore the coastal visuals are a lot nicer to look at than the sewers. Of the vehicle sections only the driving parts made a repeat appearance, with Gordon getting hold of a stripped-down muscle car in Episode Two. It works because the car is essentially a means to an end. The final battle of Episode Two involves driving around a patch of forest in a desperate attempt to fling bombs at giant armoured tripods - "striders" - whilst being frustrated by little mini-tripods who shoot the bombs. You have to collect bombs, drive after the striders, fight the mini-tripods, throw bombs at the striders etc; it's pure arcade adrenaline and it's great albeit mindless fun.

The final battle is a welcome reminder that Half-Life 2 is at heart a game. It's part of a medium in which thrills trump realism, and rightly so. The developers were not too proud to bend realism in pursuit of gameplay. For example, the vehicles that Gordon drives are indestructible; if the player drives the car off a cliff the game ends, but otherwise Gordon doesn't have to continually guard them from stray bullets.

The same is true of the other major non-player characters, such as Alyx Vance or Barney. At several points in the series they accompany Gordon during the action sequences. No-one likes escort missions. Too often the escorts are a useless burden, just like your ex-wife who just sat on the couch all day putting on weight, and also they are stupid and incapable of looking after themselves, and furthermore their friends are boring uninteresting people whose idea of conversation is to just list their trips to Waitrose in excruciating detail. That's not conversation, it's an internal monologue. It's selfish.

And you fail the level through no fault of your own. Half-Life 2 does away with this by making the escorts almost invulnerable. Freeman wears an armoured suit, but Alyx Vance only wears jeans and a jacket; the developers decided that fun gameplay was more interesting that realism, and as a consequence Alyx is actually more bulletproof than Gordon. The human rebels wear torn, faded clothes and live in squalor, but they have an endless supply of munitions; it's as if they're all sponging off their ex-husband without doing anything for themselves. At several points in the game Gordon finds ammunition crates that dispense literally infinite amounts of rockets and grenades. It's a wonder that we lost.

But we did lose. Half-Life 2 ends on a cliffhanger. Gordon defeats the baddies but is caught in the blast of a giant explosion. Does he survive? Yes, he does; the G-man halts the flow of time and transports Gordon to safety. Valve chose to continue the game with stand-alone episodes rather than a full-blown sequel. Episodic game development came into vogue in the early 2000s, but it never really caught on. Telltale Games managed to make it work with Tales of Monkey Island and Back to the Future, but SiN Episodes famously collapsed after just one episode and Valve abandoned the idea after Half-Life 2: Episode Two. I assume that the cost and difficulty of assembling a talented development team doesn't scale down to match the modest scope of an expansion pack, and on an personal level I don't like the idea of buying a half-formed fragment of a game.

The episodes were a mixed bag. On a technical level they added new high-dynamic-range lighting and some gameplay tweaks, some of which were added to the original game. Episode One begins with some exciting sci-fi action and urban combat, but has a dull final battle involving a boss monster that the player has killed several times already. Episode Two starts off with a tedious bug maze but steps up a huge notch in the second half, which is non-stop action against an intriguing new mechanical enemy that is notably smarter than the rest of the baddies.

I feel sad talking about the episodes. They remind me of the Matrix sequels. People eagerly awaited them, and for a short while they were cherished. "I was here. I existed. I was young, I was happy, and someone cared enough about me in this world to take my picture." Ten years later they are just footnotes, doomed forever to be mentioned in passing at the end of articles about Half-Life 2. Doomed forever.

The next big thing after episodic games has been downloadable content, whereby players are encouraged to spend money on trivial enhancements to the basic game, such as attractive but non-functional armour for the player's horse. Valve's attitude to downloadable content is surprisingly negative; the company charges for episodes, but DLC is free unless you have an Xbox, but that's not Valve's fault because Microsoft insisted that they charge money.

Valve's attitude towards spin-offs of Half-Life has been surprisingly positive as well. The series has produced an unusually large number of popular spin-off titles. The original game begat tactical shooter Counter-Strike and comedy cartoon action game Team Fortress: Classic, a pair of multiplayer titles built with Half-Life's GoldSrc engine. In both cases the games were unofficial fan-made modifications (Team Fortress was a port of a mod for Id Software's Quake), and in both cases instead of clamping down on them and suing the developers, Valve instead bought the rights and gave the developers jobs! The two games were followed by official sequels; as of 2016 Counter-Strike is a major franchise and Team Fortress 2 still has a strong cult following despite being nine years old. Did you have a strong cult following when you were nine years old? I didn't.

Perhaps the most unusual spin-off is Garry's Mod, which was named after developer Garry Newman, who is presumably bombarded on Twitter by people asking him if he still has the Polymoog he used on "Cars" and whether he still flies planes etc. Garry's Mod isn't a game at all, it's a construction kit that allows players to mess around with models from Half-Life, Counter-Strike and so forth, using the Source engine's physics model. It can be used as a simple level editor, but it is also fun to just throw things around and blow things up.

It includes models of the NPCs from Half-Life 2, so if you want to pretend that Judith Mossman is your ex-wife and throws things at her and drop her off a cliff, you can do that if you want. Or you could pose her body in the air and look at her bottom, or anything really. Garry's Mod was originally free but now sells at a budget price, although most of the maps require that you have a copy of Counter-Strike: Source as well, which adds to the cost. It has been downloaded over ten million times and is the kind of unpredictable success story that tends to pop up when you give people some toys and the freedom to indulge themselves.

Half-Life 2: Episode Two was the last Half-Life game. It was originally released as part of a compilation, The Orange Box, which included the original Half-Life 2 plus Episode One. Most compilations are appendices, but The Orange Box had a life of its own; it won numerous awards and sold very well. Edge gave it 10/10, which means that Half-Life 2 is the only game to receive two perfect scores from that magazine. The compilation included a new game, Portal, which was released with little fanfare. Portal combined the physics-based aspects of Half-Life 2 with a portable teleporter gun that could be used to transport the player from one part of the map to another. On the surface it was just a showcase for the Source Engine, but the gameplay and voice acting - particularly the snide supercomputer GLaDOS - were of a commercial standard. A standalone sequel, Portal 2, was one of the big hits of 2011; it is perhaps the nearest we are likely to get to Half-Life 3. The games apparently take place in the same universe although beyond the sharp design work and smart writing they do not tell the same story.

Alyx has a robot friend, DOG, who is an invincible metal punching machine. He's even more effective against the Combine than Gordon - he even manages to hurt a Combine Advisor. It's a wonder the human resistance doesn't mass-produce him.

What else? Episode Two ended with some hints of how the story would progress. The resistance had discovered a research ship, the Borealis, buried in the Arctic ice. It held a great secret that could defeat the Combine - but what if the Combine got their hands on it first?

Alas that was the end of the series. Valve suggested that Episode Three was almost finished, but it never appeared, not in 2008 or ever. A planned episode set in Ravenholm was cancelled, and although a mixture of concept art and passing references to a third game have emerged since 2007, there has been no official announcements from Valve. It's possible that Valve has been working in secret on a masterpiece, and that they will surprise us all; the company still exists as a going concern and there would be no shortage of demand for a third Half-Life game. Perhaps Gabe Newell is angry with the world. With Half-Life he showed us a better way; he showed us that there could be something better than Blood II: The Chosen. Half-Life 2 had much stronger competition, but nonetheless the writing and gameplay set new standards. How could a third Half-Life game have the same impact?

Quite easily, is the depressing answer. Nine years have passed since Episode Two but PC gaming is not nine years better. The best-selling video games are giant franchises; the few attempts to do something different in a first-person action context, such as The Line, have not set the world on fire.

Perhaps Gabe is disappointed with us. Perhaps he feels that a superb new Half-Life game would just be more of the same. The reviewers would be happy and video game fans would rejoice, but when the dust eventually settles - as it always does - the gaming world will devolve back into military shooters and empty graphical demos.

But look at what Half-Life begat; Garry's Mod and Team Fortress and the like. Strange flowers grew. The struggle has no end, and we are doomed to die; does that mean we should go gentle into that good night? No, and something might save us if we hold on long enough.

Gabe, I ask you; hit us, baby, one more time.