Hey,
I just love the tmnt. Your sprite has a lot of potential and you made a lot of progress in your second edit.
But there where still some things buggin me:

- I used cartoon shading to increase the readabillity, but i don't know if you were going for that style
- I tried the fix the arms and torso a bit, giving them more correct proportions.
- I also changed the highlight to a more yellowish green.
Hope you like it,
Ray