I just bought L4D as a part of Steam's holiday sale. The L4D2 demo worked fine, so I was expecting this to work similarly, however certain objects are appearing overlaid on top of everything else. So far all I've noticed this happening with are the helicopter at the start of No Mercy (which, now in front of everything, looks like a toy helicopter hovering above the survivors) and all the doors. It really ruins the whole feel to see a bunch of doors everywhere you look. Does anyone know what to do about this? I'm running CrossOver Games 8.1.2 on Mac OS X 10.5.8.