Not only did I fail to spend my entire Army of Two review talking about the storyline, I actually spent the bulk of it talking about the gameplay mechanics. And still missed a lot. So, you know. Do as I say, not as I do.
Either way, this is a pretty fun game. I feel like the single-player mode has actually gotten a bad rap. The only major concern I had with it is that the AI-controlled teammate was usually unable to successfully drag my character to safety and administer first aid when he was hurt. Granted, that's a significant problem when it comes up. But generally he's pretty good about going where you want him to go and doing what you want him to do, even if it's almost always easier to put him in Aggro and just sneak around melee-ing everybody to death.
Another criticism I didn't make in the review: It's kind of hard to enjoy the two-player action when everybody on your friends list is still playing Call of Duty 4 like it's their job.