Very nice shading, background, everything but... Althought the foam effect looks alright, I'd say have less foam on the first waterfall and more frames so the water looks like it's moving slower, also... the front fall kinda just looks like it's wobbling, as opposed to gushing. Not sure how you'd rectify that... I suppose have more "tween" frames.
I see you are asking for a critique! But it looks unfinished to me--it's completely lovely, except for the places where you still have hard black lines outlining the buildings. There's so much color depth everywhere else that those areas are pretty glaring.