Yeah, moving cameras didn't help. But I also had a fair few moments when I was nicely immersed and moved to the side a bit when I got shot at - one of them very nearly sent me off the side of treadmill. Haha.
A bike is almost certainly more doable. I'd actually quite like to hook an exercise bike up to gamepad at some point so you have to pedal to accelerate/run/shoot/whatever. I don't mean having the pedalling itself activate the buttons mind, more making it so certain buttons wouldn't work unless the bike was being pedalled enough.
Unfortunately, I don't have a bike. xD
What game did you play
btw?