I think there is a core of a good game here, but I have a bit of constructive criticism:
-It was very difficult to determine where I would land. I think this is a bit of a camera problem; perhaps you could tilt it down slightly in proportion to my current jump height.
-Speaking of jumping, I felt like I had very little control over it in general. I would love to be able to stop ascending by releasing jump.
-I wasn't sure what the goal was. I could infer that I needed to prevent the stadium from being painted red, but am I supposed to jump on the balls as well? It leaves a little marker of some sort when I do, so it felt like something I should be doing. Because I didn't bounce on them, however, I was penalized for trying.
-Encountering the edge of the map sends me catapulting back toward the center, regardless of my speed upon hitting it. Then I would inevitably hit a ball, which was frustrating. I think it would work better to have the wall recoil be proportional to your current speed, and perhaps reflect your angle of motion as well.