Portal 2: Peer Review

Portal 2: Peer Review includes an additional course for Portal 2 co-op campaign, dubbed "Art Therapy"; as well as Challenge Mode for both single-player or multiplayer campaign, where players can play specific levels and compete in friends/worldwide leader-board.

This DLC is available as a stand-alone product for the PlayStation 3 version of Portal 2 via PSN, and is included with a free update for PC/Mac versions of Portal 2 via Steam.