Sequel to 2007's Game of the Year Coming This Holiday March 5, 2010 - Valve, creators of best-selling game franchises (such as Left 4 Dead, Counter-Strike, and Half-Life) and leading technologies (such as Steam, Source), today announced Portal 2 for shipment this coming holiday season. Portal was originally released in 2007 and earned over 70 industry achievement awards. For more information, please visit www.steamgames.com