["Extensive single player - Featuring next generation gameplay and a wildly-engrossing story","Complete two-person co-op - Multiplayer game featuring its own dedicated story, characters, and gameplay","Advanced physics - Allows for the creation of a whole new range of interesting challenges, producing a much larger but not harder game","Massive sequel - The original Portal was named 2007's Game of the Year by over 30 publications worldwide","The single-player portion of Portal 2 introduces a cast of dynamic new characters dynamic new characters, a host of fresh puzzle elements, and a much larger set of devious test chambers"]