Great game, I really enjoy "A ha! moments" and this game provided several.
That said, two notes:
- Level 15 killed the performance for me, so I stopped there.
- I think the "challenge" of aiming it correctly shouldn't be a challenge, the game should just tell you where it will land before you click. That way, the game can focus on exploring its main (and very interesting!) concept of levels-within-levels and challenging the player to understand how it works and the implications, and less on guesstimating how far the mouse should be from the square in order to provide the right amount of force.
I would buy a polished version of that.
Like @Casual42 commented:
"often, execution is more difficult than finding the solution. It shouldn't be a game about execution."