What was done
Randomno built a matching decompilation of 3D Pinball for Windows: Space Cadet, aimed at the Windows XP SP3 release, with LLMs doing most of the work. The XP functions are almost entirely matched.
Randomno's pinball-decomp is a matching decompilation of 3D Pinball for Windows: Space Cadet, targeting the Windows XP SP3 build. The human-written README says the work was largely driven by LLMs. Almost all XP SP3 functions now compile to the same code as the original, and work on matching the whole executable has started.
How it was done
The project starts from k4zmu2a's SpaceCadetPinball, an existing non-matching C++ decompilation. The code is built with the same compiler as the original, cl and link 13.10.4035 from the Windows Server 2003 SP1 DDK, and compared against the original pinball.exe with reccmp from the LEGO Island decompilation project. Debug files from the Windows NT 4.0 builds, which include line numbers, helped show where a function was wrong. The Windows 3.1 Full Tilt Pinball build was also used for reference. The LLMs wrote the helper tools for dumping assembly and comparing versions, and the author says he has not reviewed them.
Results
XP SP3 functions are almost entirely matched, and some XP x64, NT 4.0 and Full Tilt functions were matched along the way. The only C runtime function that needed decompiling was WinMainCRTStartup. The README warns that some issues may remain. The repository needs your own pinball.exe to build.