Portal 2 Install-Game:

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 includes a two-player cooperative mode. Two players can use the same console with a split screen, or can use a separate computer or console; Windows, Mac OS X, and PlayStation 3 users can play with each other regardless of platform. Both player-characters are robots that control separate portal guns and can use the other character’s portals. Ranch Simulator

Portal 2 Free Download:

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.