Nintendo/Maxis/VGHF

































This year, we learned that a long-lost version of the classic gaming series SimCity, originally meant for the NES, had found its way from Nintendo's archives to the hands of collectors. That story got a tidy Christmas update this week in the form of a comprehensive data dump, complete with stories, videos, and—perhaps most important—a ROM download of the working, incomplete game.

Frank Cifaldi, founder of the non-profit Video Game History Foundation, posted the complete story on Tuesday. There's a lot of catch-up to be done about how the heck this SimCity version came to be, and Cifaldi breaks down some important tales, including the origins of SimCity, how Nintendo got involved, and the working relationship of game-industry legends Shigeru Miyamoto and Will Wright.

The post also recaps the story that Cifaldi told at a gaming expo earlier this year about how the prototype was discovered, and how a VGHF member eventually purchased one of two existing copies for the sake of this week's public data dump. The article makes very clear that SimCity's NES version is incomplete, and as a result, its videos and explanations are arguably an easier way to explore the game than trying to load it yourself. Accounting and math errors lead to an interesting one-two punch of glitches: your cities will develop much more slowly than on the Super Nintendo version, but on the bright side, any accumulated city "debt" will turn into cash for some reason.

Should you wish to emulate it anyway, be warned: SimCity for the NES was designed for the system's "MMC5" cartridge chipset, and some emulators, including the one that ships by default with the NES Classic, do not elegantly emulate ROMs meant for this higher-level chipset.

It's in the code

Analysis of the game's code and assets reveal a few surprises, including a wholly original soundtrack whose songs were never used in another Nintendo game (save one theme that made it into SimCity's Super Nintendo version). Animations and tiles hint at more complicated city-sim systems that would have eventually made it into the game, had it been completed, while unused animations of the game's mascot/assistant, Dr. Wright, hint at more playful moments that could have been implemented.

The disassembly team went to great lengths to confirm the rumor that this was the final NES version of the game Nintendo had ever developed. One example was an analysis of all public screenshots of this game that had existed prior to their discovery. By breaking these down, Cifaldi and his team feel confident that they have a version identical to the one briefly shown at 1991's Consumer Electronics Show.

Cifaldi concludes his article by pointing to ongoing efforts to get this NES version cleaned up enough for legitimate play via the SimCity Open Source Project . "The disassembly has all of the improvements in it already," Cifaldi said to Ars via email, and he encouraged us to peek through that repo's notes to see what's already been changed and addressed in the months since the ROM was originally shared among a smaller group of VGHF cohorts, along with a litany of bugs that still need fixing. As of press time, work on the game's fixes appears to be due entirely to one contributor

Should you wish to join these efforts, you can find nearly 2MB of the game's disassembled source as part of the download that the VGHF has made available at archive.org. (We recommend sparing the non-profit's servers some strain by grabbing the torrent file at that link.) Though Nintendo has regularly flexed its legal muscles on ROM distribution, this is a relatively unique example of wholly abandoned, incomplete software from Nintendo made available for the sake of digital preservation. Whether that raises Nintendo's notoriously litigious legal eyebrows remains to be seen. [Update, 1:52pm ET: Cifaldi has declined Ars Technica's request for comment on the legal status of this file's distribution. A Nintendo representative has offered a response "if/when" the company's legal department makes any statement.]

Listing image by Nintendo/Maxis