Campaign: same thing as always. Corridor shooter, no variety. Every mission is shooting a lot of bad guys in different settings. Nothing new and a pretty weak story.
Zombies: only thing that saves this game from being the worse one yet. Good variety in modes eg TranZit. kept me entertained for a couple of days.
Multiplayer: Worst part of the game. It set out to reward people playing the objectives and it does but it also allows people to sit in corners, not move all game and do very well. The addition of combat training with the added twist of going against other people online was interesting but this doesn't actually count as a proper game even though you gain xp. This wouldn't be a bad thing except a few people just stay on that to level up and don't go online. If you like sitting in corners, using explosives and just pay the game to make others hate you then you'll love this game.
If your looking for a decent game that will keep you entertained for hours, that has plenty of variety and won't make you wanna sell said game after one week then steer clear.