Great job! I love the art and sounds! :)
I would suggest to maybe make the game scene or level bigger, because I had some trouble seeing what exactly was going on. (Note that I have no vision impairment). I would also suggest to make the brush bigger so that you can really see what colour you are on, or maybe instead of changing the colour of it you could change the shape, because again it was hard to see.
Otherwise, great game! Keep up the good work! :D