How Id built Wolfenstein 3D using Commander Keen tech

The following excerpt is a chapter of “Game Engine Black Book: Wolfenstein 3D”, an in-depth examination of the history, code, and development of id Software’s influential Nazi-killing first-person shooter. This chapter reflects on the game’s origins and how it was built atop the success and tech of id’s Commander Keen, itself created out of the bones of a failed attempt to sell Nintendo on a Mario 3 PC port. Adrian had to first make the key decision of which colors would go in the palette (some games like Monkey Island used multiple palettes depending on the section of the game; id Software went for a simpler solution with one palette for the whole game), then draw everything with only those colors.

Source: www.gamasutra.com