I like this game quite a bit. It has a very easy to understand game loop and the art is really cute. I really enjoyed the animation and the feeback for when the balloon landed on the people. I think maybe in general the UI needs to be more visible and maybe adding an addional person that gives extra points or some kind of other feedback would make it a lot less repetitive.
Also I am really unsure if you actually "cast water balloons" - I feel that you could have gone way more interesting with the chosen theme!
Great job tho, it's really clear to play!