This is really cool, it looks really simple but the once you start moving it becomes clear what the game is, and I enjoyed it
The game started off really easy and then at level 9 the difficulty has risen quite a bit, but overall the levels were fun but a bit easy
The problem with how you used this mechanic is that in most levels it seemed like the controls were just inverted and gameplay wise it didn't affect much of how I played, the only levels that the moving world was apparent is levels 8-9, with the multiple balls
I've seen other games with this idea and what they had in common is that they used the world to move enemies and game objects, which shows the world is actually moving a lot more then how you implemented that
Still it's a well designed game with good levels and a cool mechanic, so well done!