How it works

The game shipped as a finished program, with no source code. We write each function again in C++ and build it with the same compiler the developers used, Microsoft Visual C++ 2005. A function only counts when every byte of its machine code comes out identical to the game's. Almost right counts as zero, so every number on this site is proven.

It's the same method, and the same open, AI-agent-friendly workflow, that rebuilt every in-scope function of Fallout: New Vegas. See fnvdecomp.com for how that went, and its published source.

The full walkthrough (the loop every function goes through, who does the work, what's hard) goes up here when the project opens.