I decided to only note down the cons and one pro about this game, so that this review doesn't get ridiciolously* long:
The AI. It's just bad. Their reactions are weak, and they are dumb to the point that surprise attacks from behind are too easy.
When they shoot at you, then they are unrealistically good at doing that, especially snipers. How can a sniper run around like his ♥♥♥ is on fire, and meanwhile, make perfect quickscopes that hit you everytime? And the worst is that a level has like 4 of these at the same time. Or how can a sniper see me through thick smoke, 1 mile away, and hit me with such pixel accuracy? This is just a thing that kills the fun of the game most of the time.
Multiplayer is pretty boring and not really worth it, but I can't criticize multiplayer any further because I haven't really played it.
The co-op mode is definently great and worth it, and is even the best part of this game.
All in all, I give this game a 6/10 rating. It's not THAT bad, it is still playable, but as mentioned, the AI is just something that is below okay. I'll still give it a "Recommended" mark.
*or however you spell it :V