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.

Representatives from Aperture Science, doing business as Aperture Laboratories LLC, and Valve acknowledged that public safety concerns factored into the decision. They went on to say that even though Portal 2 will arrive slightly later than planned, all life on earth won't instantaneously stop as every molecule in your body explodes at the speed of light, which is what would happen should a rip ever appear in the fabric of Valve Time.

"Also, the game will be even better," they added, missing an historic opportunity to create the first product delay press release to mention that a product is being delayed to make it worse.