I have successfully reverse engineered and decompiled Snood for the GBA (2001), a game originally created by
@GCDaveDobson over 25 years ago, entirely driven by AI. Every byte matches (SHA-256).
I used Opus, Codex, and dozens of parallel DeepSeek V4.1 agents to attack different parts of the codebase.
The first step was finding the compiler, where I sent off some agents, and they discovered it was agbcc, the GCC 2.95 compiler from Nintendo's GBA SDK, and verified it by recompiling standard library functions like memcpy and getting byte identical output to the ROM.
For the first week or so, matching was stuck at 3% as I had no idea what I was doing. Then one afternoon, I experimented with agent swarms and went from 7% to 81% in about 5 hours.
I ran over 20 DeepSeek agents in parallel in multiple waves, each AI assigned its own function in its own sandbox, so they never stepped on each other's work. The bigger AIs merged each result only after re-verifying their work, picking and choosing what was best.
The last 19% took several more days, and the last 300 bytes were very difficult compiler forensics. This work is particularly suited for agentic workflows as the reward is easily verifiable (matching rom percentages).
Why Snood?
I have a faint memory of playing this game at around 3 years old. I also remember hearing the video game soundtrack and wondering "How did they fit that in the cartridge?"
Well now I have my answer, they used the GBA's four built-in sound channels in a sort of midi-like way to generate songs on the fly. Only the sound effects are real samples, 8-bit audio at about 11 kHz.
I also wanted to choose a game that was relatively obscure, had little info, as Pokemon has been analyzed to death (and I didn't grow up playing Pokemon!)
I don't have an accurate number on the cost, but it was around 4-5 billion tokens. I do feel a bit strange, as now I was no longer tell AI what to do, I was telling AI what to tell AI what to do!
The knowledge I gained from this project is mostly high level about how to coordinate agents, rather than technical details (though, now that I have the code, I can ask any question and figure it out).
What would've taken a team of hobbyists years took me about two weeks of on and off work. I think we're about to see a lot of forgotten technology and code get preserved, which, in the face of AI writing more and more code every day, is kinda amazing in my eyes.
The future is very bright for technological preservation efforts.
If you're interested in the code, let me know below.
Enjoy the cutesy explanation video!