Left 4 Dead 2

Well, the Passing dlc was released just yesterday, and I must say it's very fun, although the campaign is only 3 missions long, in each mission you will spend some time, and in the last one the L4D1 survivors even help you, well 3 of them anyway(not going to spoil who dies). you also have 2 new weapons, the M60, a heavy caliber machine gun that has 150 rounds and cannot be refilled. And a golf club, great for smacking of infected heads. There is also a new uncommon common infected, the infected survivor, who will run away once he sees you and will drop supplies upon death. You also have a new witch type: the witch bride, who is actually a witch in wedding clothes. further you have a great new gameplay mode called mutations, wich is actually new game mode every week, ranging from versus realism to chainsaw massacre and extreme realism. All in all, I think the new L4D2 is better than the first, and definitly worth the try and buy :)