Novelty & Story
Infinity Ward puts a lot of energy into the presentation of their games, and MW2's game director, Keith Arem, is even working on a full-fledged film. So what kind of impression did the story leave on me?
It seemed uneven. The cinematics were incoherent, and only sullied the amazing emotion and novelty of its in-game moments. This is your only warning: BIG SPOILERS AHEAD!
It's unfortunate that cinematics are a problem. Where most games do a better job producing cinematics than producing emotionally arresting play, MW2 commendably does the opposite but still leaves me wanting. Because the locations and events of each scenario in the game are so jarringly different, the cinematics become important for gluing together events. But the dialogue and visuals do little to set up the why behind each level scenario. At best, they successfully describe the gist of missions (e.g., you are an inside-man so keep up appearances; or you were betrayed so the Russians have been turned against us) but do little to distinguish the reasons behind my locale and mission (e.g., why am I in an airport gunning down civilians, exactly; or why am I climbing up a snowy cliff into a Russian base, exactly). If these were explained, they slipped by me, and I walked away with the same disjointed experience I did in Modern Warfare (1).
The connection I had in play, however, was often great. I may not have understood why I was in an airport, but watching "allies" I'm supposed to be support for the sake of a disguise gun down civilians, and expect me to do the same for appearances, was powerful, and made the moment of betrayal, when my "allies" kill me, all the more wrenching. And when NPCs help me scale cliffs and invade bases together, and -- when I pay attention to orders -- help me survive difficult scenarios, they become real characters that I am emotionally invested in and wanted to see survive. Like the Uncharted or Half-Life 2 teams, I feel the Infinity Ward team is pushing the bleeding edge of emotional resonant characters in narrative-driven games. As much as you aren't pushed out of it by constant frustration in death, there is powerful emotion behind the Modern Warfare experience.
Novelty is the last thing worth mentioning. I remember Peter Jackson saying that as a director, it was his duty to give audiences something they have never seen before. I think the same thing is true of game designers. Though having a gun pulled on me and getting shot in the face or watching in a Ghillie suit reveal themselves was something I had already seen, there were so many other situations and settings I had not, with such high-fidelity. I loved climbing snowy cliffs, storming ruined capitol buildings, being lifted out of an exploding prison on a zipline, murdering civilians to maintain a secret identity, and just stopping to stare at one of the most beautifully rendered mountains I've seen in a game.
One final comment on multiplayer and reviews in the next and last installment...