Update: According to a GameStop listing, the game will offer a separate two-player cooperative campaign. Some details on the single-player campaign were revealed as well.
The full listing reads: “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.”
Original story: The long-rumored Portal 2 has been officially confirmed. “Valve…today announced Portal 2 for shipment this coming holiday season,” the company wrote in a short but sweet announcement.
Details remain scarce, however, the first info on this “full-fledged, standalone sequel” will be revealed in a 12-page cover story in GameInformer’s April issue; the mag will be shedding light on “new gameplay mechanics, storyline, and some surprising new twists,” they say.
Valve’s VP of marketing Doug Lombardi tells Eurogamer that Portal 2 will be a PC and Xbox 360 release but, for now, that’s where the official information ends.