 Most of the game's soundtrack is non-lyrical ambient music composed by Kelly Bailey and Mike Morasky, somewhat dark and mysterious to match the mood of the environments.The closing credits song, "Still Alive", was written by Jonathan Coulton and sung by Ellen McLain (a classically-trained operatic soprano) as the GLaDOS character.A brief instrumental version of "Still Alive" is played in an uptempo Latin style over radios in-game.