 The game was first playable at the Showdown 2007 LAN in San Jose and at QuakeCon 2007.Turtle Rock Studios announced "Left 4 Dead" on November 20, 2006, and was acquired by Valve on January 10, 2008, because of the game and long-standing relationship between the companies.The game opened up to pre-purchasing on Valve's Steam system on October 15, 2008.