Portal is a single-player first-person action/puzzle video game developed by Valve Corporation. The game was released in the bundle package The Orange Box for Microsoft Windows and Xbox 360 on October 9, 2007, and for the PlayStation 3 on December 11, 2007. The Windows version of the game is also available for download separately through Valve's content delivery system, Steam and was released as a standalone retail product on April 9, 2008. A stand-alone version was released on the Xbox 360 Live Arcade system on October 22, 2008; this version also includes fourteen bonus puzzles. [source:wikipedia]