I can't find any powerups, and full speed doesn't get enough height to hit it, plus, I can't seem to bounce the ball to get it either... I don't know what else to try.
There's a secret technique that isn't mentioned anywhere. If you let the spin meter hit the top, and then stop it in the perfect zone on the way down, the throw will be slightly faster. That should be enough to get you up there!
As someone who aspires to make games, (failing with the getting to learning programming, and fixating on game design), might I suggest adding some minor bit of additional visual feedback to signal success at this technique?
The ball being a little faster seems too subtle to signal to a player that anything is different, but giving a vague indicator that's easier to spot could give players more room to piece together this technique exists through passive experimentation.
(edit)
I'm realizing now that the text saying Amazing instead of Perfect may be just that.
