Having just finished this game, I am a little confused about all the negative reviews. Yes the game is shifting away from the old school "Horror" theme that some fans me be used to. However, what makes this game great from a campaign perspective is that with 4 different unique characters the replay value is high. Beyond that every characters campaign is unique so you get a different feel for the game throughout.
The campaign is long and exciting and I for one was very pleased with it.
This game had alot, For hardcore fans it ended up being a slight let down, mainly because of the fact they changed the gameplay quite abit [in my point of view] I think playing it alone, is kind of boring though, playing Co-op with someone you know [or atleast mic] is quite interesting though, kept me going through it despite the fact i do not find much enjoyment in it, i think the "agent hunt" [where you are a special zombie type trying to kill agents as they play the story mode online] is awesome but, the problem with it is that its far to easy for the players to win and you to lose, other then that one mode flaw, this is a good game and if you are bored i'd atleast give it a shot