I really like the idea! It is really fun to come up with solutions for each level and the cool thing is that there can be more than one solution.
I also like the minimalist art style even though it is a bit inconsistent.
However the controls feel a bit weird. The ball feels floaty and heavy at the same time. It is really hard to judge how it will handle.
On top of that you need to work on the collision shapes in the game. The balls feels like an egg instead like a ball and sometimes even hovers over the ground.
I think the game needs a bit of "Juice". It could be way better by just adding a sound plus a camera shake when the player dies etc. This can make your game feel way better.
Finally after you finish a level, before you proceed to the next level. You can still move the ball and still die. I would disable keyboard input to prevent that.
But I think it is a really good game and with a bit of work it can be great! Keep it up!