Today Valve released a new video that shows off some of their developers running through games like Portal Counter Strike: GO and Civilization 5. The devs show off how the track pads act much like how a mouse works and it appears to work well with most games.
In the video you can see an picture in picture setup that showcases the controller as the game is being played. Personally, I don't know how I feel about the controller yet. I am hoping that Valve will have it on display at CES for the media to try out.