The Animal Crossing Secret You Probably Didn't Know About
In a way, this hidden Animal Crossing item was a secret buried inside a secret — and a pretty cool one, at that. You might have discovered the first one — but chances are, you had no idea the second ever existed.
If you played the Nintendo GameCube version of Animal Crossing released in 2001, you might have discovered that the developers had hidden entire playable Nintendo Entertainment System games within the title. You could obtain them while digging around your island or taking part in Tom Nook's lottery. Each emulated title looked like a NES system with one game box on top. Once you interacted with one, you could play the game represented on the box. If you had a Game Boy Advance and a link cable, you could play them on that portable system as well.
That was a pretty rare and exciting Animal Crossing Easter egg in pre-Virtual Console days, but there's more to this story. One NES system contained its own special secret.
Playing whole games inside Animal Crossing
TechnoBuffalo reported in 2016 that each Animal Crossing game had at least 10 classic NES titles embedded within, and others could be obtained through giveaways. These included Balloon Fight, Golf, Pinball, Tennis, Donkey Kong, and Excitebike. Some players using a particular cheat got The Legend of Zelda, and a few lucky players in Japan received Super Mario Bros. as a giveaway.
This is a pretty good selection of classics, but as it turns out, there was a way to play any NES game through Animal Crossing. You could accomplish this using another item, generically called the "NES console." It had no game box on top, and when players tried to interact with it, it would say there was no software. But it turns out, this NES device was a load-your own emulator that could play any generic NES ROM stored on a GameCube memory card.
It was an enterprising security expert named James Chambers who figured it out in 2018. His very technical explanation basically says that the NES program in question is designed to mount and search your GameCube memory card for compatible ROM files. Using his debugging and tweaking skills, he got the game to recognize NES ROM files and loaded Mega Man, Pinball, and BattleToads onto the GameCube. He was even able to add in a homebrew ROM test that he created years after Animal Crossing's release.
Why did Nintendo include this Animal Crossing secret?
In an alternate timeline, perhaps Nintendo created all sorts of plans using this feature on the GameCube version of Animal Crossing. It could have been used to add new content to the physical version of a title, long before DLC was a thing.
A Twitter user floated the idea that Nintendo might have had plans for kiosks that could write NES content to personal memory cards. Chambers theorized it might have considered releasing GameCube memory cards with preloaded ROMs. He told Kotaku he thought Nintendo once planned to add more NES titles to Animal Crossing.
"They already put a fully-working NES emulator into the game, so adding the capability to load more games in with a memory card wasn't much more work, and would've allowed them to possibly sell or give out promotional copies of these memory-card based NES games," he said.
Either way, it appears the possibilities available through this built-in feature never actually materialized. However, if you're familiar with video game hacking, you can try to create your own NES ROM file for Animal Crossing to read on the GameCube. The source code comes from Cuyler36 and is available here.