Portal™: Still Alive (Valve/Microsoft): Portal: Still Alive features the full award-winning Portal single-player game from Valve plus a new challenge mode. Designed to change the way players approach, manipulate, and surmise the possibilities in any given environment, Portal has earned more than 70 industry honors for its innovative gameplay, with more than 30 Game of the Year Awards. Solve physical puzzles and challenges by opening portals to maneuvering objects, and yourself, through space. The game debuts on Xbox LIVE Arcade in 2008.