Amazing
This is probably the best and most enjoyable single-player game that I've ever played. I'm not one for shooting games, but this one had shooting that was just hard enough to be satisfying but not so hard as to be frustrating. Acutally, that's the way I felt about the whole game; hard enough but not too hard.
And when you've finished the single-player, you can jump on the co-op or competitive online modes!
Fantastic!