Valve announces free co-op shooter Alien Swarm

This Monday, July 19, Steam will be releasing Alien Swarm for the low, low price of free. Two years ago, Valve hired a group of modders behind the popular Unreal Tournament 2004 co-op mod called Alien Swarm. The team has since contributed to popular games such as the Left 4 Dead Series and Portal 2, but on the side, they were hard at work on a Source version of Alien Swarm, and the fruits of their labor will be released on Monday – for free. In addition to providing the game free of charge, Valve will release its complete code base, including updates to the Source engine SDK and full Steamworks integration to provide 'more insight and examples' for aspiring modders and small-time developers.

Available free of charge, the game thrusts players into an epic bug hunt featuring a unique blend of co-op play and squad-level tactics. With your friends, form a squad of four distinct IAF Marine classes. Plan your attack using an unlockable arsenal of weapons with countless loadout configurations against a wide variety of aliens. Blaze your way through an overrun, off-world colony, eradicating the alien infestation in environments ranging from the icy planet's surface, to a subterranean lava-flooded mining facility.

 * Tactical, 4 player co-op action game with a top-down perspective
 * Complete game code and mod tools
 * Unlock persistent items by gaining levels
 * Over 40 weapons and equipment with countless loadout configurations
 * 4 unique classes and 8 unique characters
 * Matchmaking, Steam Cloud, Steam Stats
 * 64 achievements
 * Tile-based map generation tool
 * Powered by Source and Steam