I actually was at PAX East and got to play the demo for Child of Eden. There was no discernable lag that people are complaining about here. It was very playable. It was also relatively simple an intuitive to understand. It was an on-rails shooter, definitely, but instead of using a gun peripheral (a la Time Crisis), you use your hands. It was commented on by one of the people at the booth, and I agree, that it gives you the feel of having "superpowers". The only thing that was difficult for some to get the hang of is a proper motion for firing the lock-on shots, as moving your hand can move the reticle, and sometimes it might not register. However, it can be done. One of the demoers that I watched had it to a science, and I wasn't too bad at it either. I guess, as with any active game, it comes down to how coordinated you are in your movements.