Nothing There
Even when the environment changes the map is too small. Also, no matter what map you find yourself joining, the objectives, the way they happen, the little missions that come up ... are all the same.
The campaign in this game is a joke since it doesn't deviate from what the game looks like online (the only difference is that you play the systems bots instead of real people who are signed in).
Seems like this game was rushed on the market so it could get out before Halo and Modern Warfare 2. My advise is to save your money - if you have the game already trade it in on one of the two titles just mentioned because either of them will surely have a better Live version that this game.