Alien Swarm is a co-op squad-based shooter UT3 mod. Set in the distant future, the players take the role of a Commander in the Interstellar Armed Forces. They must guide their squad of marines through Swarm infested colonies, overrun bases and outposts, to achieve a variety of objectives.

Featuring Assault Rifles, Heat Tracking Guns, Sentry Guns, Flamethrowers and more. Alien Swarm can be played single-player or online co-operative multiplayer, with a strong emphasis on teamwork between the marines in both forms of play.

Alien Swarm is now on Steam, as a Source Mod.