Portal

Portal is a single-player first-person action/puzzle video game developed by Valve Corporation. The game was released in a bundle package called 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 called "Still Alive" was released on the Xbox 360 Live Arcade system on October 22, 2008; this version includes an additional fourteen puzzles. A Mac OS X version was released as part of the Mac-compatible Steam platform on May 12, 2010.

The game consists primarily of a series of puzzles that must be solved by teleporting the player's character and simple objects using the Aperture Science Handheld Portal Device (ASHPD, also dubbed the portal gun), a unit that can create inter-spatial portals between flat planes. The player character is challenged by an AI named GLaDOS to complete each puzzle in the Aperture Science Computer-Aided Enrichment Center using the portal gun with the promise of receiving cake when all the puzzles are completed. The unusual physics allowed by the portal gun are the emphasis of this game and are an extension of a similar portal concept in Narbacular Drop; many of the team members from the DigiPen Institute of Technology that worked on Narbacular Drop were hired by Valve for the creation of Portal.

Portal was acclaimed as one of the most original games of 2007, despite being considered short in length. The game received praise for its unique gameplay and darkly humorous story, created with the assistance of Erik Wolpaw and Chet Faliszek of Old Man Murray fame. It also received acclaim for the character of GLaDOS, voiced by Ellen McLain in the English-language version, and the final credits song "Still Alive" written by Jonathan Coulton for the game. The game's popularity has led to official merchandise from Valve including plush Companion Cubes, and fan creations such as recreations of the cake and replicas of the portal gun. A sequel, Portal 2, was announced in March 2010 for release during the 2010 holiday season.