Well I tried my hand at a partial edit.
I edited the left half only.
Looking at it closely I see a lot of "pillow-shading" ( shading a shape inward ). You do this in a lot of spots.
You're coloring also looks very grainy, like stone, not like metal. Metal is clean and shiny. I didn't get a good metal look myself but I think I did a better job defining volume. Even that is tough because you have some detail there that is confusing.
You're way too heavy on the black, and you make it worse by adding dark colors around the black outlines. I can't think of a term for the look that this creates but let's just say it looks amateurish. Adding black outlines to all the little detail flattens the image. You just don't have enough space to outline all the little detail in black. Use contrasting colors to make detail.
Your wings look like big stone paddles. Why the bulge in the middle? Why aren't they straight? If they are going to curve it should look more aerodynamic.
And I'm sure there was something else I was going to say but it escapes me at the moment. Hopefully my less-then-perfect edit will illustrate what I mean.