I'm really impressed that you were able to put together a 3D game in such a short time, with terrain height variation and everything!
I was confused at first by the water gathering. I was looking at the meter on the side of the robot which fills up long before it is actually ready. Only after skimming comments, I realized it wasn't full and that was why I couldn't water the terrain.
In the future, it would be really cool if the surrounding terrain also changed beyond the small circle when you water. For example, the texture could slightly change to a slightly more luscious color. Was the plants and trees that popped up procedurally generated where they go? It felt like that was the case since at one point a flower popped up where the drain was, and that is a hefty thing to mess with in a game jam!
I could see this being such a vibe/chill game if you decided to continue development on it.