You can't really know if something is usable without using it. After making pyShiva, I wanted to use it to make something I couldn't have easily made without it, and so I spent a day making a game demo. At the same time, I wanted to experiment with gesture-based interfaces.
The result: engulf, a frantic quest to consume nutrients and grow larger while escaping a cloud of enemies.
The gameplay and control scheme are finely tuned to take advantage of the Kinect; you must change your avatar's appearance and size in order to eat food of the appropriate color while dodging between narrow gaps formed by the enemies harrowing you at every turn.