Hi Seiseki!
This looks really good. Sadly I only got around to editing this now.
I originally tried to animate the whole thing, but working without layers (and having to simulate them myself) was too much grunt work, so I decided to only edit the first frame to at least get some ideas across.
I edited your clouds, because I thought they were a little lacklustre. I'm not a cloud person though, so do take this with a pinch of salt.
I messed a bit with the lightsource on her suit, because really it looked like you just copy-flipped a lot of it and that's naughty!
Then I tackled the hair. I read something about struggling with it, so I focused mostly here. I've cut some of her hair (the bits that were crazy long compared to the rest); added some volume by adding a lot of bunched up, darker hair behind the front stuff; and critically I've added strands to her hair so it no longer looks like tentacles!
As far as animation goes, I was thinking of letting the boat rock up and down rather than just going up one pixel altogether and then down a few frames later (like a seesaw), move the clouds across the screen slowly and animate the hair in a more... jellyfish kind of way.