With the black dawn release, of course I had to try it out, it was quite fun, but I ran into a really annoying bug several times:
Basically, the game completely froze without warning for like 10 seconds, afterwards going completely black for 5 more seconds, and after that, the game resumed, only the ground wasn't getting rendered anymore (In other words, it looked like I was walking on air. Stuff other than the ground itself (plants, rocks etc) looked just fine though. No clue what exactly caused it, but I had it happen quite a few times during the campaign. The ground rendered fine again after the next loading screen.
Windows 7 64 bit
4 GB of ram,
Amd Phenom 2 x4 945 (3 GHz)
Also, I was playing with video settings (other than antialiasing) maxed. Feel free to ask if you want more info!