Very cool. Did anyone else notice that the direction of many of the gestures were reverse of the "natural" motion. I.e. to scroll left, the hand gestures to the left, rather than to the right as if you're dragging the viewport to the right. Also, to zoom in, the thumb and index finger are brought together, rather than spread apart as if you're dragging to points on the viewport away from each other.

Obviously this would all be configurable but it's strange to work on something to reduce HCI friction while using a design that's counterintuitive.