Seeing this 0 reply post left on the front page of this forum section for so long was bugging me

But what also bugged me was I tried to fix this up a few days ago and sort of failed. I had another bash at it today and it looks a little better then my previous attempt, so I thought to post to see if this might give you suggestions/ideas on how to re-work your sprite.
I think my main issue was the tiny resolution, it was really quite tricky getting this looking like the source material and I commend you for your efforts, It was much more of a challenge then I first thought.
Ok so I made a little sequence picture for you so you can see the iterations I went through, I started with your original, then started fresh with the detailing and shading, but trying to maintain your rough shape. The rest I hope is easy enough to follow in the picture.

I struggled to get the turtle neck looking right, struggled with the face, in particular the eyes, struggled with the feet.. the result is a much leaner sprite that might be perhaps easier to animate, there is also a tiny bit more space on the face you could could get try get alternate emotions with the mouth area, I think I lose a bit of that "anime" look, but perhaps it might be a bit closer to the source material, I dunno.., my face is still really messed up. anyway,
I am sure someone with the sort of talent I see around here could improve this a lot more though.
keep trying/experimenting, practice, practice, practice