Hey there!
I am new to this community, tho I have been active in others like r/PixelArt. I will just say from the get go that I feel a bit embarrassed to just go ahead and ask for critique right away, but I hope to give back in the future.

So, to the art and what I need some help with.


This is a mob in a game I'm working on which is a type of RPG that sets in an alien world. These aliens look like in the picture, more like robots.
Though it may look decent I can't really put my finger on what exactly I do not like about this piece, but I think the "anatomy" is not portrayed properly with my lightning and and shading.The light is coming from the upper left.
One thing that bothers me is how the "ribs" ( the purple light on his torso) should look. How much of the left proportional to the right ones should be visible.



Here I have a second version that I think has improved the look, but it still doesn't look right to me. I'm having a hard time figuring out how to paint a 3D object in 2D, or rather I know how to kinda imagine it in 3D space, but I can't put that same information into pixels.
Any comment is really appreciated and I want to continue working on this mob until I'm satisfied with the result.
If anyone has any suggestions to improve the colors its is also very appreciated, as I'm not too happy with those either.

Thanks in advance!