Development of SNES Wii Virtual Console

Published on 19 Jun 2026

The post is sourced from internal emails at Nintendo during the development of the Wii, leaked in 2021 as a continuation of the Nintendo gigaleak of 2020.

So Nintendo had a NES emulator and a N64 emulator before the development of Wii Virtual Console, but they didn’t have a SNES emulator, and you might remember the story where Retro Studios did implement a way to play Super Metroid in Metroid Prime on GameCube, but Nintendo refused because the developer opted to use an unofficial SNES emulator to make it work, though another reason on top could also be legal issues in relation to a part of the SNES emulation, which will be explained later.

Eventually, the need for a SNES emulator was serious, and Nintendo began development of a SNES emulator at the Integrated Research & Development Division (IRD), usually responsible for hardware development. The development was helmed by Paul Donnelly, visibly one of the few non japanese employees at Nintendo in Japan at the time.

Early plans of SNES Virtual Console releases in 2005 included SuperFX games like Star Fox and Yoshi’s Island, as well as Super Scope games and SNES Mouse games for much later.

Most people would kind of reasonably think that the SNES emulator would just accept any ROM like that but… that’s not quite the truth.
The main reason is that at the time, Sony owned the patents behind the way the sound compression works on Super NES, and it was made clear at Nintendo to avoid infringing on these. So they had to devise a way to bypass these patents, and the way was to extract all sounds from a SNES ROM into a seperate file (a PCM file) and replace all sound data in the SNES ROM to point to that file instead. Keep in mind that Nintendo had to continue to do this until Wii U and 3DS, it’s only starting from the Super NES Classic Mini that they took it upon themselves to finally emulate the Super NES sound correctly without hacks because all the Sony patents in relation to it are now expired.

Changing the sound data like this is by no means an easy endeavor, and the emulator was conceived with ways to more easily reverse engineer games to do these changes, alongside other changes such as ways to remove flashing lights and more in an effort to be more accessible to people sensible to them.
There were tons of checks and tests, comparisons with the original hardware to the point of digging up old development kits for deeper analysis, to really make sure the experience is respectable, even writing brand new manuals for these games. These are time consuming tasks that most people aren’t necessarily aware, and this is also across other emulated systems.

At one point in the development of the SNES emulator, it was planned for Intelligent Systems, already in charge of the NES emulator, to also take over the SNES emulator project. The project was not really ready to be given to Intelligent Systems yet, Paul wanted to clean up the code in a way that would be easy to share with them first. Except he couldn’t quite have the time to do that, because he would then have a skiing accident that would put him to a hospital. Don’t worry though, he’s okay!
His co-workers checked on him, while also talking about how to handle how to pass the baton to Intelligent Systems, now pretty much the priority to hopefully keep everything on schedule. Paul would eventually work again on SNES emulation later on, once he recovered. Intelligent Systems SNES programmer veteran Genji Kubota took over development of the SNES emulator and game hacks. His familiarity of the hardware helped development and debugging with his experience of the old development kit (IS-DEBUGGER, aka the japanese version of the Super NES Emulator SE development kit).

Thanks to the strange inclusion of game lists inside the emulator, we can also get an idea of which games have been considered, and sometimes actually completed: Among those games we can include EarthBound, Picross NP Vol. 1 to Vol. 4, Super Bomberman 3 (down to even using the unreleased US ROM), Tetris Attack, Aladdin, Super Puyo Puyo (it didn’t release in Japan), a Virtual Console release version of Super Mario All-Stars as well (before they decided to make one of the worst anniversary celebrations ever with it on Wii), and some more, especially missing games in Japan like Marvelous, Shigesato Itoi no Bass Tsuri No.1, SD Gundam G-NEXT (the last two are notable to me for being Satellaview compatible games). The list also suggests a potential japanese retail release of Secret of Mana in Japan using the Virtual Console format, similar to Dragon Quest 1+2 and 3.

There were mentions of tight schedules to a point where visibly everything was still being worked on until the last minute, it seemed. And releases were kind of based on what was ready on the moment, especially considering that the emulator was new, and that they still had to emulate the extra processing chips of SNES games later like the DSP-1 (Pilotwings), SA-1 (Super Mario RPG, Kirby Super Star and Kirby’s Dream Land 3), CX4 (Mega Man X2), S-DD1 (unused, intended for Star Ocean which was considered).

And at the risk of repeating myself, each game were managed deeply, each ROM had to be modified to avoid patent infringement and anti-epilepsy concerns, they also had to be tested and debugged, as in played for actual hours (I’ve seen more than 60 hours spent on Fire Emblem in internal spreadsheets), also managing rating boards submissions, writing brand new manuals because you couldn’t fit scans, like, frankly, even if the emulators are less accurate than the community ones, I do think most people do not consider the work that was put on Virtual Console games, and it followed until Wii U and 3DS too.

It’s only until Switch that they changed their ways after the cancellation of Switch Virtual Console, which I’ve done some history here.