 Portal 2 contains both scored and procedurally generated music created by Valve 's composer , Mike Morasky , and two songs ; " Want You Gone " recorded by Jonathan Coulton , used on the final credits of the single @-@ player mode , and " Exile Vilify " by The National , used in the background of one of the Rat Man 's dens . The full soundtrack " Songs to Test By " , containing most of the songs in the game , was released as three free downloads between May and September 2011 , and later in October 2012 as a retail Collector 's Edition , including the soundtrack from Portal . 
