I can't play the game but Nintendo World Championships NES Edition can be preloaded and has a 1.1.0 update already.
— Yakumono (@LuigiBlood) July 11, 2024
It's indeed developed by Nintendo and indieszero.
...so the codename is "Fake" (yep) and it uses NERD's NES emulator (NES Mini, NSO).
NES World Championships developer revealed via datamine
The title is the latest of Nintendo’s secretive collaborations
The developer behind Nintendo’s upcoming Nintendo World Championships: NES Edition has been revealed.
As uncovered by dataminer Yakumono, the files for the game’s Nintendo eShop preload confirm that Nintendo created the game in collaboration with Indieszero.
Indieszero is a small, Tokyo-based studio which has collaborated with Nintendo frequently in the past, notably on the NES Remix games, Big Brain Academy, and Dr Kawashima’s Brain Training for Nintendo Switch.
Yakumono also claims that World Championships uses the same emulation software as Switch Online and the NES Mini, rather than the older Wii U software.
Nintendo has recently adopted a secretive approach to the developers behind its video game collaborations, frequently declining to confirm the identity of game creators until after release.
Recently, the company was secretive about the developer behind Princess Peach Showtime, declining to confirm if Good-Feel was working on it when asked. It was similarly secretive about the developer of Luigi’s Mansion 2 HD, and it’s currently unclear who’s working on the new Mario & Luigi.
Previously, it was similarly secretive around the developer of Switch’s Super Mario RPG until its identity was discovered on a store page.
Nintendo World Championships: NES Edition is a retro challenge compilation for Nintendo Switch, featuring 150 speedrunning challenges divided across 13 classic NES games.
In VGC’s recent Nintendo World Championships: NES Edition preview, we wrote: “After an hour of competitive, tense, and often hilarious gameplay with Nintendo World Championships: NES Edition, the speed-running classics collection feels like the Switch maker’s next multiplayer hit.”