This game is unfortunately unplayable due to several bugs that ASPYR have not yet fixed and with their track record of 'support' I'm not holding my breath.
Although I get cut scene issues like sound but no video or flickering un-watchable video, the main problem for me is the sound. It wont play in 5.1 without the sound being messed up. ASPYR, rather then fix it said play the game in 2.1....
On some levels nearly all the sound disappears making you very vulnerable to attacks from behind as you don't hear anything. This makes the game seem badly programmed and frustrating to play.
Most if not all users of the Steam version had this problem with sound. The companies involved would not fix it, but one member of the public fixed part of the problem himself in this thread:-
Anyway, What I'd suggest is not to waste yr money on this broken game until there is a patch that address all issues. Just read the problems in the forums, that should be enough to put anyone off.
(By the way I have several games and all of them play fine, I have all latest drivers for everything and nothing running in background that should cause issues. System;- i7 920, HD5870 x 2, 6Gig Kingston Hyper-x RAM, Rampage Extreme II MB. Soundblaster X-Fi.)