In early 1991, Nintendo announced SimCity for the NES and SNES. The Super Nintendo version actually came out in April that year, but the NES version was dropped. Now a prototype of the game has been extensively analyzed and put online.
The Video Game History Foundation has posted an extensive article online detailing SimCity for the NES. Although the game was never released, a cartridge containing a prototype of the game appeared at a retro games fair last year. The foundation committed to preserving game history obtained the cartridge and was able to digitize and analyze it.
Nintendo announced the NES version of SimCity at the Winter Consumer Electronics Show in 1991 and then showed some screenshots. The promise was that the NES version would have the same features as the variant for the SNES, the new 16-bit console from Nintendo that would be released that year. SimCity designer Will Wright teamed up with Mario and Zelda creator Shigeru Miyamoto to port the game to Nintendo consoles.
According to the Video Game History Foundation article, the most unique aspect of the NES version is the size of the tiles to build on, which measure 2×2 instead of 3×3 like the PC and SNES versions. The early version of the game also features a soundtrack by Soyo Oka, who was also responsible for the Super Mario Kart and Pilotwings soundtracks.
The digital assets of the NES version of SimCity have been put online at the Internet Archive. These include the soundtrack as an MP3 and a ROM of the game, which can be played with emulators.