Hey there, cool little puzzle game! I think the idea works nicely. I didn't play too far in, just to level 5 I think. But I had some good moments, and felt engaged. From playing those levels though, I will say I think the levels with the boosters feel a lot more fun than the levels without. On level 5 I think it was (back and forth), there was a dip for me, because it felt like I was trying to force the ball to move along. And it kept just crapping out. I was drawing ramps at the most slightest angle so that I could try and get it to go the distance, which I don't think it too great of an experience. Seeing the ball whiz around a loop and off a ramp is there the fun is.
Also, this might be a stupid question, but why a cube instead of a sphere? A sphere somehow seems more fitting for the idea, and the corners aren't really relevant anyway. That might also have more nuance in how gravity interacts with your ball (as opposed to on/off) with the cube. Eh, just a thought.
Nice work! Puzzle games are hard to get right imo, and you've gotten past most of the pitfalls/mistakes I see a lot of games make.