Here is my constructive crit =)
I like all the detail work in this piece. It looks quite impressive. I can see that you stylistically like bright lights, and a glowy effect. Because this is a design piece, like a poster, it works. I would seay the main improvement for this one would probably be the smokey effect. I get the impression it is supposed to be smoke, but I am unsure. It seems to be undecided, like it doesn't want to go all out. It wants to extend from the metal, but it isn't as slowy or floaty as it could be. I think if you want to have smoke, do it. If you don't, then don't. Because it looks undecided, I'm not sure what it is, and why it is there. I also think there could be more variation in the colors. I see about 3 or 4 shades of yellow, and about 4 shades of gray, but I think you can have more variation. In real life, if you look at a vehical, metallic surfaces are effected by the environment and the lights around it. I would expect bluish bits near the parts near his eyes and chest lights, and maybe tealish parts on the parts of his metal near the edges. Same with the gray bits. There can be parts which are more yellowed, blued, etc, which will increase the depth of your image.
Overall, great job.