Portal 2 is a physics-based puzzle-platform game created by Valve and released on Microsoft Windows, Mac OS X, PlayStation 3, Xbox 360 and Linux in April 2011, followed by a Nintendo Switch version in June 2022. 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.
The game's music includes original scores composed by Valve's Mike Morasky, and two original songs provided by Jonathan Coulton and the band The National. The bulk of the music was released as a freely-available download across three volumes, entitled Songs to Test By, and later in a four-disc retail Collector's edition that included music from Portal.