Really nice game, glad I checked it out! The visuals are beautiful and very clean. The mechanic was simple but the difficulty increases very subtly, until I stopped at level 11 to take a break. Was quite relaxing really :) The only thing I missed was some more aural feedback, maybe.
As another Unity developer, you really need to tell me how you did the liquid droplets shader, as well as the digging channels for them to flow through. Awesome stuff!