I rented this game, and freakin loved it. I got into the city, and brought the game back then. I was about 8 hours in, and only 23% through the campaign.....gotta love campaigns like that!! I think this game is basically Oblivion, but with zombies. I really enjoyed it. Playing single player, it actually sent chills down my spine when I'm fighting a zombie and one comes running up from behind! I'll be picking this up next paycheck, and going through co-op with my friend.
What have you heard about online play?