Nothing at all !!!
First briefly about the campaign: Okay, interesting but eventually extremely boring. I play CoD since 2nd part, so I've already experienced and seen but this is just the last! Okay a new unity, a Fede, which is so clear how unnecessary. The only thing I liked was the sniper rifle that is usable via laptop.
Multiplayer: Oh come on ... stop. After BO2 I thought really what the heck developers are thinking about? Hardly spawn already dead. I've really tried to make friends with the game but ... nope. Just no. I left so much nervous already in Multi BO2 of that I here just after about 10 hours online, have drawn a line.
Both games, BO2 and this one, were sold immediately and I came back to MW3 and I love it.
Let it alone, let's play the Yanks: P