Well, I stumbled upon this graphics glitch, it's everytime when I go into another level(like, when I fresh start the game, it isn't there until I change the level). For better explanation, I've included a screenshot:
It's mostly on his hand, but also on doors, curtains...
I've got the newest drivers(ForceWare 258.96) installed.
CPU: AMD Athlon 64 X2 3800+
GPU: nVidia GeForce 8600GT 256MB
RAM: 2GB DDR400
I've also tried disabling the post process effects without any result, turned on anti aliasing, also didn't work. SSAO is turned off. Texture details are on high, shadow quality is on low, shadowmap size is on medium. VSync enabled, but disabling it doesn't works too.
Also this is the only game this happens in, never had this problem in Penumbra.