http://video.google.com/videoplay?do...tal+demo&hl=en
Check this out, it's the next great thing from Valve. It will ship with Half-Life 2: Episode 2. it apparently ties in with the current Half-Life story, but you dont play Gordon Freeman. it is a puzzle game, and to my knowledge there are no actual enemies save the environment and robot sentries. your only weapon is an "Apeture Device" that lets you create 2 interconnected dimensional portals. If you have played Prey, you are probably already familiar with this concept.
Coupled with a gravity gun like function, this looks AMAZING. from what I can tell, the plot is very similar to the movie Cube.