Zombie Panic Source

Zombie Panic! Source (ZPS) is a cooperative survival horror Half-Life 2 Modification, the sequel to the popular Half-Life Modification "Zombie Panic". As a member of a party of survivors you find yourself without provisions or any military support.  Fending off the undead has never been more difficult, but with a large variety of fire arms, explosives, and unique items, the task is not impossible.