Portal 2 is a physics-based puzzle-platformer game created by the Valve Corporation and released on Microsoft Windows, Mac OS X, PlayStation 3 and Xbox 360 in April 2011. The game, set in the desolate, labyrinthine Aperture Science facility, challenges the player to navigate test chambers created by the artificial intelligence GLaDOS, using a portal gun, a device able to create portals that link two points in space like a wormhole. The game expands on the original Portal by adding new puzzle elements, such as paint that imparts properties to surfaces, plates that can launch the player and objects over distances, tractor beams and bridges made of light.