Really nice platformer. Everything moves silky smooth. I really enjoyed the game play too.
The player sprite is nicely animated (although maybe you could animate his hair as nicely as the rest too
One minor problem: I turned off music, but while I was playing, the music turned itself up again.
Maybe you could also give players a little bit of feedback about what to do in the first level. Most people (including me) don't want to read how to play so it wasn't immediately clear to me that you had to return those water bubbles to the trees. I even thought there was a bug when I couldn't get any more bubbles. You could display a little text message in those cases that you have to return your bubbles to the trees.