The L.A.-based studio's first projects were doing contract work for Valve on various titles in the Counter-Strike series, including a port of the original CS to Xbox, Counter-Strike: Condition Zero, and several maps for Counter-Strike: Source. In January 2008, Valve announced that it had acquired Turtle Rock.
While at Westwood Studios, Michael Booth worked as a programmer on Nox and the technical director for Command & Conquer: Yuri's Revenge. He was inspired to found Turtle Rock in 2002 as an alternative to larger, more corporate development environments.
Turtle Rock announced its first original IP, Left 4 Dead, in 2006 and showed hands-on gameplay for the first time in 2007.
The game features cooperative zombie battling, with four survivors (either AI- or player-controlled) who must work together to make it through the various levels intact.
Notable is the game's dynamic AI system, known as the "Director"; instead of using fixed spawn points in the levels, the "Director" places enemies in randomly determined locations each time a level loads, keeping gamers on their toes.
The game has generated a great deal of enthusiasm in the game community and was impressive enough to inspire Valve, arguably the king of the independent studios, to buy them.
Left 4 Dead is due to be released this November for PC and Xbox 360; the game will be retail published by Electronic Arts.
"Internally, Valve has always referred to Turtle Rock Studios (now officially Valve South) as 'Valve's fourth floor,' a reference to Turtle Rock's Los Angeles-area fourth-floor office space.
The joke illustrates the symbiosis the two developers already had pre-acquisition, when Michael Booth's startup provided maps and updates for the Counter-Strike franchise.
With the zombie co-op extravaganza Left 4 Dead, which brings years of multiplayer expertise to bear,
Turtle Rock is sure to gain a much more public following."
- Chris Remo