Having trouble running the game...

But my system requirements exceed that of what it needs. I'm running it on steam, and the major issue is something with the shadows (I think). I've tried everything I can think of for fixing it with no luck. The problem is that everything is flashing really dark and back to normal, but most of the time staying in the really dark version. It's playable, but annoying as hell. Anyone know a solution? (I have an GeForce GT 650M graphics card, 2.1GB dedicated video RAM, 8 gigs RAM and Intel Core i7-3615QM CPU @ 2.30GHz)