distribution half-life 2: deathmatch
Left 4 Dead is a cooperative first - person shooter video game with survival horror elements , developed by Valve South and published by Valve Corporation . The game uses Valve ' s proprietary Source engine , and is available for Microsoft Windows , Xbox 360 and OS X . Development on the game was completed on November 13 , 2008 , and two versions were released digitally : A downloadable ___MASK18___ version , released on November 17 , 2008 , and a ___MASK18___ retail disc version , with a release date determined by region . The ___MASK18___ retail disc version was released in North America and Australia on November 18 , 2008 ; and in Europe on November 21 , 2008 . Valve Corporation ( commonly referred to as Valve ) is an American video game developer and ___MASK7___ company headquartered in Bellevue , Washington . The company is known for the " Half - Life ", " Counter - Strike ", " Portal ", " Day of Defeat ", " Team Fortress ", and " Left 4 Dead " series , " Dota 2 ", and its software distribution platform Steam . Half - Life 2 : Deathmatch is a multiplayer first - person shooter video game developed by Valve Corporation . Released on ___MASK16___ on November 30 , 2004 , it uses many of the assets from Half - Life 2 and its Source engine . It features new levels , optimized for multiplayer arena play , and a few new weapons . Also included are portions of the game ' s source code , which were the basis for many early Source - based multiplayer modifications . The game is the successor to the popular multiplayer component of the original Half - Life , but is offered as a separate product from Half - Life 2 . Deathmatch , like Half - Life  '  s multiplayer , does not develop any part of the plot or story of the Half - Life series . Half - Life 2 ( stylized as HLF - LIFE ) is a first - person shooter video game developed and published by Valve Corporation . The sequel to 1998 ' s " Half - Life ", it was released in November 2004 , following a five - year , $ 40 million development phase , during which a substantial part of the project was leaked and distributed on the ___MASK99___ . The game was developed alongside Valve ' s ___MASK16___ software and the Source engine . ___MASK7___ ( also called content delivery , online distribution , or electronic software distribution ( ESD ), among others ) is the delivery or distribution of media content such as audio , video , software and video games . The term is generally used to describe distribution over an online delivery medium , such as the Internet , thus bypassing physical distribution methods , such as paper , compact discs , and VHS videocassettes . The term online distribution is typically applied to freestanding products ; downloadable add - ons for other products are more commonly known as downloadable content . With the advancement of network bandwidth capabilities , online distribution became prominent in the 21st century .