Some time ago I had a play with Image 2 ZX Spec, a piece of software that converts images into the image format used by the old ZX Spectrum. The machine could display fifteen colours at a resolution of 256x192 pixels, with the quirk that it could only have two colours in each 8x8 pixel block. You can see the effect above - the Spectrum had hi-res monochrome with low-res colour mapped on top, and it looked odd when things moved. The odd colour map and the clever dithering is the reason why I have to use specialist software rather than a bunch of Photoshop actions.
Stormlord, which was written by Rafaele Cecco, with graphics by Hugh Binns