Portal 2 - Xbox 360, PS3 and PC
Valve didn't actually show anything they haven't already revealed, but when the footage is this good I couldn't help but remain impressed. Besides, looking at Portal 2 a second time allowed me to focus on the incidental details - the pneumatic tubes, the factory lines and the laboratory slowly stitching itself back together. Case in point: as you activate an Aperture Science Sentry Gun production line, the robots all switch on at exactly the same time - lighting the room up in hundreds of flicking red dots. It's absolutely gorgeous, with an art direction that few other games will be able to match.