The game was first released for Microsoft Windows on 22 November 2011.[3] The OS X support for the game followed shortly after and was released on 23 April 2012.[4] The Linux version of the game started being worked on after a high number of requests, where the first Linux-related update was the porting of the game's dedicated server.[5] The game itself, however, was released one day after Valve opened the beta branch for "Steam for Linux", namely 20 December 2012.[6]