Generally solid but let down by buggy multiplayer and a short campaign.
I enjoyed the campaign although I thought it could have been longer. That said, this game is lethal on the "Veteran" difficulty. I can't count the number of times I died trying to man the 50 cal MG on the Humvee as it was driven through the cramped streets of some dusty Afghan town. The suspense and drama are perfect and I genuinely felt upset at some points. Of course I won't say when, so as not to spoil the storyline. Suffice to say, the buildup to the final mission and the climax of the story is excellent.
Although I was upset that the campaign could not be played in either online or offline co-operative, this was offset in part, by the addition of the "Spec Ops" missions. This gives you the opportunity to work with (or in some cases compete against) your friends in a variety of missions that fall outside the main storyline. As they are separate to the storyline, these can provide a refreshing break and encourage teamwork a lot more than the online multiplayer.
The multiplayer was probably the biggest disappointment for me. Although the decent level of character progression had been built on since the earlier titles, I saw considerable bugs which were exploited by some players. I had the same connectivity issues although this is more down to my playing through a router than the game itself. That said, I play other online games without these problems so what is it that makes Call of Duty games so special? Overall the multiplayer left a sour taste. The maps are great and the variety of weapons and killstreak rewards is immense but the bugs were a considerable downer. And where, to put it bluntly were the tanks? Infantry combat alone, can get boring!
Overall, this game felt fairly solid, but wasn't as well polished as I had hoped.