Alien Swarm

Alien Swarm is a top-down shooter produced by Valve and is the successor to the Alien Swarm mod for Unreal Tournament 2004. Made in large part by the original team, Valve has made the game, mod tools, and code free to all Steam users.

In Alien Swarm, players take the role of a member of an elite squad of soldiers facing The Swarm&mdash;a mysterious race of creatures bent on killing anything, or anyone, in their way. Fighting their way through hordes of aliens, players may choose from one of eight characters (across four classes) and over 40 weapons and tools to eradicate The Swarm.