Valve has revealed today that the first free Portal 2 DLC will be arriving on PC, Mac, Playstation 3, and Xbox 360 on October 4th. This DLC is titled Portal 2: Peer Review and you will continue the co-op story that features an all new mysterious test track were you will be playing as Atlas and P-Body once again to outsmart GLaDOS in a bunch of new puzzles.
Peer Review will also be adding a Challenge Mode for both single player and co-op were you will be able to compare score against friends and the Portal community on the leaderboards.
