Developer Maurice Hoijburg published a project report on October 9: his team spent three months and consumed over 500 billion tokens of compute, deploying AI agents to decompile the 2009 Call of Duty: Modern Warfare 2 and rebuild it as C++ source code. Led by Hoijburg, the team included community members such as RektInator, Future, and st0rm.
Initially, the team ran agents in parallel across two command-line setups, Claude Code and Codex, with models covering Sonnet 5, Opus 5.5, Luna, Sol, and Terra; tasks were dispatched via GitHub Issues and progress was synced in Discord. In the first month only 4 agents were deployed—three dedicated to breaking down commits and one for review. Although this got the game to launch, show the menu, and load maps, and cracked about 80% of the functions, the generated code was merely "readable," with semantic errors lurking in function signatures, types, and even logic.
Byte-by-byte comparison drives out high precision
The real turning point was a "byte-for-byte match" verification: the original compiler was used to rebuild the object files, and every function was compared byte-by-byte against its counterpart in the original EXE and PDB—those passing were marked PASS, those failing were sent back for rework. To prevent agents from cutting corners, the team disabled tricks such as inline assembly and naked functions, and used CI to compare script hashes. In the later stages, 14 Luna plus 2 Opus 5.5 agents each submitted PRs on independent branches. Ultimately, 99% of the game's functions made it into the rebuilt code, with 83% achieving byte-for-byte identity with the original; Heumann said the code will not be released and is kept for private use only.