Premise: Portal 2 . It is the sequel to Portal ( 2007 ) 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 .
Hypothesis: Portal 2 was released for Linux.
Label: ENTAILMENT