What I noticed was the feeling of speed - the game does a remarkable job creating a frantic feeling of falling! However, I agree with josh that the camera sometimes makes it hard to see what's coming. That might have something to do with the fact that the game was designed initially from the side; perhaps it would have been more open with more space to move if initially designed from this perspective? The feedback through the Debug.log statements was mostly successful, but I did find myself sometimes wondering how many lives I had. (We haven't covered UI, but it's something to think about - changing the color of the sphere to indicate health, or something else on the screen...)