Portal

Portal is a first-person puzzle game developed by Valve Corporation and released in late 2007, first as part of The Orange Box for Windows, Steam, Xbox 360 and the PlayStation 3, and later as a standalone title for Windows and Steam. In the game, the player controls a female test subject named Chell in the Aperture Science Enrichment Centre. Guided by a female electronic voice-over of a supercomputer named GLaDOS, the player uses the Aperture Science Handheld Portal Device ("portal gun") to perform a variety of tests, such as creating portals to knock over turrets and other objects or moving to a previously unreachable area, so that the player may advance to the next test.

Portal's development team consisted of several people who attended DigiPen Institute of Technology and worked on Narbacular Drop, a freeware game that had concepts similar to Portal.

Portal is set in the universe, as indicated by explicit references to Black Mesa in the game. There are also many similarities between equipment in Portal and in Half-Life 2; turrets, for example, are quite similar in both games, and Portal also uses energy orbs identical to those in Half-Life 2. The backstory to Portal is explained in Half-Life 2: Episode Two, although the story behind the protagonist is explained throughout Portal.

You awake as Chell, a woman equipped with implanted heel springs to help her survive falls from great heights, in the middle of a relaxation room. Immediately, the mechanical voice of GLaDOS greets you. It's time to be tested as a human lab rat. Will the experiments go as planned?