Cool concept. I think it just needs an instruction at the start of the game (or my guess is that you're still working on the game).
Gameplay-wise, I think it's still a little rough to grasp what players need to do for the first-time players. So, maybe add a bit of text/image to teach the players what's their goal is. And maybe just a thought of switching the genre from score-based to level-based puzzles perhaps?
Nice game for mobile players by the way, my high score is 800.
Edit: I will rate it later :)