Very interesting idea for a game, although a little repetitive after a while as it doesn't get easier or harder.
When I first played and the ball fell, my first instinct was to avoid it. I then proceeded to fly around aimlessly wondering what I was supposed to do for a few minutes.
Some kind of indication that the ball was not an enemy could be helpful, like perhaps an arrow that points to the ball as it falls for the first 5 seconds that says "catch" and an arrow that points to the trampoline that says "bouncy" or something. These can then fade once they've been understood.
I enjoyed the concept, overall a nice idea.