Another huge oversight which they only fixed 2 days ago was only enabled 2GB of virtual memory on 64bit OSes. This made most 64bit OS people I've spoken to crash every few minutes. How did that get past QA?
Of course, it could be fixed with a patch on the EXE someone released. Until they encryped the EXE (to prevent piracy) and broken the only fix people had for a month.
A 32-bit executable can use 2 GB on both 32 and 64 bit OSes; there's a linker flag that lets you use 3 GB, if you're not playing any dirty tricks with your pointer bits. More than that, and you need to recompile the EXE for 64-bit, which is far from trivial, and uncommon for games. Especially games that also run on 512 MB consoles.
Of course, it could be fixed with a patch on the EXE someone released. Until they encryped the EXE (to prevent piracy) and broken the only fix people had for a month.