Reversed an old video game pretty extensively for me. Got it running in 30 minutes, then patched some bugs, reversed the entire game logic VM and rendering pipeline, and we're now in process of expressing game logic as Lisp and upscaling assets for rendered that it already made to operate at 4x its hardcoded resolution...

Starting point was literally original installer copied over from a CD, which I hold on to and dug up from an old hard drive, plus a short prompt asking to make it work. Installing Ghirda and developing a whole framework for patching the binary, as well as substituting DirectDraw with its own DLL shim, was Claude's own invention.