The GAMEMAPS checks are based on known releases of the Wolf3D and SoD products (see the ECWolf Wiki for the listing I used, since I don't own all versions).
If your GAMEMAPS was ever modified at all, it won't work.
Belated reply to this post...EdalgmGaming wrote: ↑Fri Jun 27, 2025 5:15 pm Looking through the code, what's The Ultimate Challenge UAC Version?
The original release of The Ultimate Challenge had several different wall graphics in the finale level.
The version that seems to be more prevalent (Activision release) is one that was supposedly originally sent to the ID team as a preview/joke that had some Doom-texture derived wall graphics.
You can see comparison images and details in the first post here.