Saving you the trouble of coming all the way out to LA, IGN have published off-screen video of the Portal 2 demo Valve’s currently demonstrating here at E3. The first gives you a bit of story background — taking place as GlaDOS resurrects herself years after the events of the first game — while the second two below the fold dig further into the new gameplay features, including the “propulsion pudding” paint-gun enhancements added when Valve employed the fresh student indie team behind Tag: The Power of Paint.
The best part? As always, the hapless turrets and your merciless blanking of them a minute or so in that first video.