picked up this game 2 days ago, and I'm addicted. not a zombie thriller, but definitely a zombie killer. The only decent way to play this game is online, and either play with friends or pray for a decent party. There's nothing like mindlessly slaughtering hordes of undead, unless you happen to wind up with idiots on your team.

only downside is the fact that there are only 4 levels, a weak amount of weapons, and there's no customizable characters. Kinda feels like valve skimped on this game...