I know, everyone right now is playing other fresh game on front page of steam, but you might be missing other one. It is in 3D and even set in Portal universe! But... it is just a demonstration of new hand controller for Vive where you can use each finger and put different pressure into the game.
Anyway, it's playable and you can try it, if you have usual Vive set. We can take it as small step from games as services toward good old single player experience. Or am I too optimistic?