We were just playing around with this specific app in our office. There were about 5 guys huddled together, spinning around with the person controlling the iPhone. Quite a sight.<p>Playing with the gyroscope myself, I realized there is actually a very comfortable degree of motion you can make holding the phone for <i>added</i> game input. I don't want to be spinning in circles trying to shoot bad guys, but some extra rotational movement is nice.<p>Also, for being an early game (maybe the first to adopt the gyroscope?) the spatial input was very intuitive, it took about 3 seconds to orient myself with the device and it was all blam-blam-blam from there.