have you lit this with sun and sky and put a stary background behind it in PS? It looks like the tube things are reflecting the sun and sky environment.
Also what is going on half way down the big horizontal tube things? there are some "wires" that disappear into nothing.

Imo your textures are pretty basic, have you used layered shaders to make them? I only ask as you said that you build up the layers like 2D painting.