The first Portal 2 details have emerged revealing that the game will feature coop, improved physics, the return of GlaDOS and much more. The information comes from the latest issue of Game Informer which includes a feature on Valve's next big game. Valve stated that the company was surprised by the original Portal's success, calling it a "test bed," while the sequel will apparently be a much more comprehensive game.
GlaDOS, the villain from Portal, and Chell, the protagonist, will both return for the single player narrative, set hundreds of years after the original. The coop campaign, set around two bipedal robots, will be completely separate from single player, featuring a distinct story and puzzles. Both campaigns will feature an improved physics engine capable of sending wind through portals, a portal next to a vent sucking wind into another portal was just one example.
Portal 2 is due out this fall on Xbox 360 and PC. Check out the latest Game Informer for more information.
Source: Game Informer