This is a great little project that allows you to navigate and do your web business without ever having to click on bit of the virtual screen. Although a little migraine inducing as the screens change constantly it is actually quite simple to use.
Contextual actions for such an interface (normally provided by right mouse click) will have to be programmed in from the beginning as part of the UI. A pretty big plus is the removal of tendon damage from all the inane clicking we do.
Another aspect of this type of interface is that with a simple projector and a flat surface (i.e. a desk) you could even use your finger OR a stick to move around the virtual space and options.
I dig (single g) it.