Claim: On April 19, 2011, Portal 2 was released.

Portal 2 is a 2011 first-person puzzle-platform video game developed and published by Valve Corporation . It is the sequel to Portal -LRB- 2007 -RRB- and was released on April 19 , 2011 , for Microsoft Windows , OS X , Linux , PlayStation 3 , and Xbox 360 . The retail versions of the game are distributed by Electronic Arts while online distribution of the Microsoft Windows , Mac OS X and Linux versions is handled by Valve 's content delivery service Steam . Portal 2 was announced on March 5 , 2010 , following a week-long alternate reality game based on new patches to the original game . Before the game 's release on Steam , the company released the Potato Sack , a second multi-week alternate reality game , involving 13 independently developed titles which culminated in a distributed computing spoof to release Portal 2 several hours early .   The game retains Portals gameplay elements , and adds new features , including tractor beams , laser redirection , bridges made of light , and paint-like ` gels ' accelerating the player 's speed , allowing the player-character to jump higher or place portals on any surface . These gels were created by the team from the Independent Games Festival-winning DigiPen student project Tag : The Power of Paint . In the single-player campaign , the player controls protagonist Chell , awoken from suspended animation after many years , who must navigate the now-dilapidated Aperture Science Enrichment Center during its reconstruction by the reactivated GLaDOS , a powerful supercomputer . The storyline introduces new characters , including Wheatley -LRB- Stephen Merchant -RRB- and Cave Johnson -LRB- J. K. Simmons -RRB- . Ellen McLain reprised the role of GLaDOS . Jonathan Coulton and The National each produced a song for the game . Portal 2 also includes a two-player cooperative mode , in which the robotic player-characters Atlas and P-Body -LRB- both voiced by Dee Bradley Baker -RRB- are each given a portal gun and are required to work together to solve puzzles . Valve provided post-release support for the game , including additional downloadable content and a simplified map editor to allow players to create and share test chambers with others .   Although some reviewers initially expressed concerns about the difficulty of expanding Portal into a full sequel , Portal 2 received critical acclaim , particularly for its writing , pacing , and dark humor . The voice work of McLain , Merchant , and Simmons were also praised , as were the new gameplay elements , the challenging but surmountable learning curve , and the additional cooperative mode . Some journalists ranked Portal 2 among the best games of 2011 , and several named it their Game of the Year . Portal 2 has since been hailed as one of the greatest video games of all time .