Let me just start off by acknowledging that your pixel art has really become something of a marvel. Just utterly beautiful to behold. Even in just your edits here and there I find a lot of awe inspiring stuff.
Moving on, I don't quite know enough to analyze the style relative to the rest of the piece, but as far as what you've attempted to go with I'd say you've hit the nail pretty damn square on the head.
I remember Sohei making some waterfalls a little while back (
here; also the
WIP thread) and I'd say it's on the same vein.
If I had to give any advice at all I'd say perhaps space the falling 'wave' out more as it goes further down to give it the feel that gravity has increased it's velocity throughout the fall?
Otherwise if you do have the time, try out Friend's suggestion, because I'd love to see the result.
Keep up the good work!