Video games don't really fall under the same category. I mean, you've got games like Street Fighter 2 in which there were several games released under that title (SF2, SF2CE, SF2T, SSF2, SSF2T... etc) and then after that, you've got different versions per platform... Arcade, PC, SNES, MegaDrive (Genesis), etc. You have games that were released with better graphics - King's Quest V, Monkey Island 1 PC, Super Mario Bros 1-3 SNES.

It is unlikely you can consider such games altered, since on their original platforms in their original versions, they were never altered. And remember that not all games came initially on only one platform, so there would never be a truly "pure" version of that game.