Portal 2 is an upcoming first-person (first-person shooter) action (action game)/puzzle (video puzzle game) video game, developed by Valve Corporation. It is the sequel to the critically acclaimed 2007 video game Portal (Portal (video game)) and was announced on March 5, 2010. Though initially expected to be released in the last quarter of 2010, it has been pushed back for a 2011 release for Microsoft Windows, Mac OS X, PlayStation 3 and Xbox 360 platforms.