Very stylish! The sound fits the graphics, the tutorial is seamlessly embedded in the game world. Great work!
The game itself is very difficult and at times frustrating. Often I found it simpler to just push the ball instead of hitting it. Maybe you could prohibit pushing the ball and force using only boxing to move the ball. And make the levels more forgiving ... maybe something more in the direction of boxing-golf: When you do a bad hit, you do not fall off the cliff but are in a suboptimal position to continue ...
I see a lot of potential in this game!