I know how they are cracked (http://news.ycombinator.com/item?id=1343066). I was wondering why no one was doing a file compare on the original Myth cracked exe and the one from Steam.

But you're wrong about game exes being packed by release groups. There is nothing to "hide" from other groups. Once you remove the commercial protector (SecureROM, etc.) the rest of the patches are pretty trivial.