Cool! Fantastic idea.
Just installed it, but it really suffers from the x-rotation shimmy (quickly tilt your head up or down, and the view will get an unwanted sideways (y-rotation) movement). - Something to do with the Coriolis effect I think.
We could really do with some proper sensor-fusion output for motion sensing built into AppGameKit, rather than just access to the sensors.
See:
At around 17:05 he talks about these weird spikes in the accelerometer data (which is what I'm seeing in your app), and how to compensate that with the gyroscope data to smooth it out.
Quote: "sensor fusion algorithms must be used in order to create responsive, accurate, and low noise descriptions of motion."