A very original concept! I don't think I've seen a game where you control a shower head before. The mechanics were simple and functional. Music and art complemented each other well.
There didn't seem to be any reason to turn the shower off. You could have it affect the score, like getting less points for each dirt the longer the water is on, for example.
The floor tiles could go with softer colors to make it easier on the eyes, and to bring more contrast to the strong-colored dirt.
Congrats on your first game jam!