Alien Swarm

Alien Swarm is an exciting free-to-play game and Source SDK release developed by an exceptional team at Valve, many of whom have roots in the Mod community.

Dive into an exhilarating experience where players embark on an epic bug hunt, showcasing an engaging mix of co-op gameplay and tactical squad strategies. Join forces with friends to create a squad of four unique IAF Marine classes. Strategize your assault with an extensive, unlockable arsenal of weapons and countless loadout combinations to face an array of alien foes. Charge through a besieged off-world colony, combating the alien threat in diverse settings, from the frigid surface of a frozen planet to a subterranean mining facility engulfed in lava.

In addition to the game, you’ll gain access to the complete code base for Alien Swarm, featuring enhanced updates to the Source engine and SDK. Experience the exciting new features brought to the Source engine, including a third-person camera, depth of field effects, improved dynamic shadows, and a wide range of gameplay enhancements.