needs a link and not just an name drop of the source image, especially if the image is traced from the original artwork.

Shading could use more work in my opinion. But i like the designs

 Ok. I'll try to improve this. Thanks for the tips. In the next work I'll get just one point of light, and shade everything with this.

Once again, Thanks for comment. 

each bodypart is shaded as indivudual elements, rather than shaded as a whole body. the orange strips do not follow the shading of the belly, wich in the end leads to everything look out of place on that area.

besides that, the whole desing suffers from an excesive use of  details outlined that simply tear the whole thing apart. (you dont need an outline for everything on this, when the shading and base color give enough definition the viewer can integrate them easily and even help it look way more smooth). remember that a 1px wide line is way more than the pixel it is made of. the whole point of pixel art is use each pixel and beyond to its fullest.

 Valeu ;)

 Very Good !

 Hm... I understand what you said. Can you give some tips to improve this? I really can't see where I can change.

that second one is one unreadable schene you decided to use. the lack of proper shading on the whole set doesnt help either