Things feel "off" in the gameplay. That "off" feeling either low-budget or just crap games can have.
Like I said in another post, the combat has one "revolutionary" feature I think. When you pull off a headshot, the game slows down a bit for half a second to a second. This gives a skilled player enough time to line up another headshot, which can put you in a chain of headshot slo-mo's. I liked that one thing very much.