Very nice.
I quite liked the levels from 5 onward, as the puzzle of how to split water evenly makes it really interesting.
Could potentially carry a full game, if you have to split between 3 pipes and have one or two interacting systems on top ( maybe have to make steam from your water, before cooling it down again, as a way to have "inverted gravity" water, while the rest is unaffected? )
Had you already played "Where is my Water?", because that would be another game where you dig to move fluids into goals. Though I don't think they made a gravity switching mechanism in any of the version I have tried.