looking at the last picture I see a few things I would work on if I was you

1) the tail - make it so it's a little fatter in the beginning and pointy at the end ( I see you did that but not enough)

2) He looks like he hasn't eaten anything in weeks... give him a bit rounded belly

3) at the start of the wings, do the same as the tail, a little thicker so it looks like they can support the wings

4) the front hands need a bit work

everything else is looking good!

-Emo