I like how the bounce sound is little bit different every time you hit the wall or floor.

This game is super-chaotic with the balls bouncing on every thing and it feels like playing a pinball for the first time.

I kinda agree with sinfulmar, where power gauge or stopping the cannon while holding/aiming probably could make it less chaotic and more controllable for the player. But, if you want to make it feels more like a pinball game, you already on the right direction :D

It can be better with power gauge, directional line, and stopping the canon while aiming