News: PS3 owners, start your petitions.
Kotaku dug up Portal 2's brand new listing on GameStop's site and discovered that when the game ships later this year it'll come with a co-op mode. Obviously, Valve wasn't ready to reveal this information to the world just yet and GameStop has since destroyed the evidence. But since nothing ever really disappears on the Internet, Kotaku also has the full original text describing the co-op mode:
Coming this holiday. Portal 2 is the sequel to 2007's Game of the Year and draws from the award-winning formula of innovative game play, story, and music that earned the original over 70 industry accolades. Features single and multiplayer co-op modes. The single-player portion of Portal 2 introduces a cast of dynamic new characters, a host of fresh puzzle elements, and a much larger set of devious test chambers. Players will explore never-before-seen areas of the Aperture Science Labs and be reunited with GLaDOS, the occasionally murderous computer companion who guided them through the original game. The game's two-player cooperative mode features its own entirely separate campaign with a unique story, test chambers, and two new player characters. This new mode forces players to reconsider everything they thought they knew about portals. Success will require them to not just act cooperatively, but to think cooperatively.
One thing Valve is ready to reveal though is which platforms Portal 2 will appeaar on. Doug Lombardi, the company's Vice President of Marketing, has told Eurogamer that Portal 2 will be released on the PC and Xbox 360. Sorry, PlayStation 3 owners.
We'll have more soon.