According to a tweet from
Gametrailers,
Portal 2 will be releasing DLC on October 4 (c'mon videogames, I've told you October 4 is
spoken for, and I'm not going to say it again!). Called
Peer Review, the new co-op test track furthers the adventures of P-Body and Atlas as they continue to be subverted by GLaDOS.
Peer Review also features a new single-player and co-op Challenge Mode complete with leaderboards so you can rub your friends' noses in the fact that you completed a puzzle .02 of a second faster than they did. Best of all,
Peer Review is completely free. You'll be able to download it on XBL and PSN on October 4, while Steam will download it automatically for PC and Mac users
.