White knuckle action.
Infinity Ward has absolutely perfected FPS controls. Even going back to old classics like the Halo series, I throw away dozens of grenades accidentally trying to look down the sights of my assault rifle. The left trigger has now become my aimer, always. It fits so well.
The story is my biggest concern though. While the action is frantic and the set-pieces are amazing, most of the story gets told through lifeless narration during load times while you stare at a blue map. I rarely knew what I was doing or why because I had to get all my context during my load times. Give me some cutscenes, something slightly interactive if you hate movie-like cutscenes so much. Just show me Soap sitting at a table in a breifing room. Anything, just give me something to look at while you tell your scatterbrained story in a less lazy format.
There is a middleground between Metal Gear Solid's ten minute videos, and Call of Duty's zero. Look no further than Half Life. You're never taken out of character, you're never bored, and can explore all you want, but they don't strip the story at the sake of a faster pace. The old man wants to tell you something, even if you choose to run to the other side of the room and stare at the wall while he does it.
Another thing is, the silent protagonist. Why? RPGs do it so you can project yourself onto his actions. Does this matter in a brisk FPS? Would anyone feel less interested in shooting faceless enemies if Roach actually talked? This was most annoying later in the game (SPOILERS) when you became Soap. The instant this happens you lose a really cool character, because he goes dead silent and practically exits the game. It becomes the Captain Price show. Why? There were some great chances for Soap-Price dialogue. Missed opportunity. Also when it comes to story related gripes, and continuing my major (SPOILERS), how many times are you going to kill me? I mean in Modern Warfare, the nuke scene was shocking and brutal. But after getting shot in the head two different times here, it was no longer shocking. Once they showed they were willing to kill you, the third time they threatened it, I no longer cared because I knew I'd just be put in the shoes of another faceless soldier. You'll be shot in the head a bunch of times, stabbed, blown up. Everything. But it doesn't matter because you're not keeping a character you care about alive. You're simply moving the game forward, and your faceless player who exists only as a codename is fully expendable. Unlike Mass Effect 2 where I literally held my breath when Shepard made his last gasp effort to leap into safety. Even though he was a different character with a voice of is own, I was more attached to him than the nothing character who I'm supposed to be pretending to be.
The graphics are amazing as to be expected. And the multiplayer is fast, addictive, and perfect. You'll sink hundreds of hours into it if you let yourself. This game is pushing video gaming experiences forward into mainstream and exciting ways, but due to some story flops, it's less than perfect. The story itself makes no sense, and you'll have to check your brain at the door, but you'll love it. (I mean really, 6 guys can't shoot up an entire 2010 airport, leave one dead American body behind and call it World War 3. Sorry, but we have forensics, cameras, and a UN. It's not that easy.)