I'm impressed and fascinated with the flooding and erosion tech here, very nice! Kinda looks like the one in Minecraft and in some city-builder games. Graphics are nice to look at, you made great use of contrast so every object is clear and distinct.
As for the gameplay, it's a decent demo and could be very well turned into a mobile puzzle game.
It doesn't necessarily need any background music, but ambient sounds and effects will definitely improve the feel of the game. 😊
For the strat, I might've cheesed it a bit, by placing a pump at the beginning (no toxic pipes yet) to the largest high-terrain, whichever is nearest to the side. It worked 2 out of 3 times. Is this the way you're meant to play it?
Anyway, I could see this game holds potential, and could grow outside of its current gameplay boundaries. So overall, great job on making it! 😄