Super cool idea for a puzzle game! The menus look real top notch too.
This feels like it was made for a tablet so some of my issues with the interface might have to do with that. It would be nice if deleting drawn sections could be done with the right mouse instead of having to toggle between the two mods. I ran into a bug where individual dots spawned from clicking the mouse button down could not be deleted. I might have missed the reset button but one of those would be nice if it doesn't exist.
I also ran into some frustration with the physics. It felt like a lot of my time was spent tweaking a solution to work with with physics after I had figured out the answer. Giving the ball a little extra force as it comes out might go a long way in helping with that.
Turning the cube with the arrow keys also felt a little awkward. It would be nice if the cube could just be rotated with the mouse.
Looking forward to seeing how this turns out!