At first, after playing the first few levels I didn't really think that there was anywhere that these levels could progress in difficulty. But wow, you managed to create some pretty complex levels out of such a simple mechanic. The sound design is also great, very ominous, and along with the screen shake it makes the game feel so weighty. Very well built game. I could see this as a full game people would play on their phone or something. Only thing was I think that I encountered a bug, in one of the levels I was able to complete it without going forward in the level at all, by somehow hitting the other ball through a wall.