Fox is a game for the Commodore C64 that was never finished. The developers Lucas Pope and Pete Gonzalez worked on the game in 1996 and have now made the unfinished source code available. The game preview indicates a number of 2D multi-scrolling levels, with some 3D Doom-styled sub sections for certain parts of the game. You can read more about this game on the Games That Weren't web page.