Really fun and exciting...at first.. Online is amazing.. with descent teamates Content = lacking
It is a great game and i would recommend buying it if for nothing else the multiplayer experience. Playing coop with a friend sitting beside u isnt something quite as fun as it seemed to be in days of past playing side scrollers together and such. So if you have someone else in your household that enjoys gaming then get this game and play with them. Or they can tag along as a guest on xbox live if they dont have their own xbox live gold account.
Online play is actually where the game really shines.. and frustrates. When playing with normal people just wanting to have fun this is a great experience because it provides a great challenge for both teams... surviving against the zombie horde is difficult if your teammates arent really helpful and concerned with your well being. Playing as the zombie's is a blast and the most fun ive had in this game.. strategically positioning yourself to get ahold of a straggler and destroying them before their teammates can help is very satisfying. the side effect of being a zombie - you die easy, but hey... you do respawn.