Success will require them to not just act cooperatively, but to think cooperatively. This new mode forces players to reconsider everything they thought they knew about portals. The game’s two-player cooperative mode features its own entirely separate campaign with a unique story, test chambers, and two new player characters. 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 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. Portal 2 draws from the award-winning formula of innovative gameplay, story, and music that earned the original Portal over 70 industry accolades and created a cult following.