Nice idea, really fun :D

Nice idea. I think a few things would improve it for fun and challenge:
Increase the speed of the spin every 5 points.
Randomise the starting angle.
Allow the player to press a button to speed up the spin manually. If they score while the speed is increased, give them bonus points.

It feels way too easy and repetetive. All it takes is for the opening to be somewhat infront of you and when you click the ball seems o automatically move, you could try to slow down the ball and make it more visible to add onto the difficulty.

Nice idea, well done on the execution :)