Was playing the pirated UK version which was surprisingly different and more difficult. Bought it yesterday 9.15 and the Gamestop guy said it was out on Friday 9.12?
Anyways, I had put in 6 hours into the UK one until a show stopper happened that prevented me from going further. That was the Cracks fault, not the game.
Played the US version last night for 4 hours straight, not one crash. I am playing on Vista x64 SP1 just to get the DX10 stuff! Very nice! I played the UK version on the same system, dual boot, Win XP Pro Sp3.
I think the game is great! No problems, its different enough from the first one but with some nice improvements. The swamps are scary as hell! The nights last too long since you cannot sleep or pass time, and screw going out at night!
Anyways - IF YOU LIKED STALKER, YOU WILL LOVE THIS ADD ON!