This is really awesome! I could never do something like this. I would like to comment on 2 things that bother me when I look at this (since you requested critique): 1. Those 2 shiny highlights at the top on his armor? (on his right shoulder and left side of his chest, from his view) I think it can be more dramatic and shiny. It looks like you made a pinkish brush stroke and then blurred it? I would recommend making some strong, edgy highlights. And then duplicate them, change blending mode to screen and then blur and play with opacity for the blurry shiny effects. (Saw this method on a tutorial one time.) 2. Secondly, I would like to see some flame definition in his boosters, with perhaps some shades of yellow or red, just so it's not pure white. As it is now it looks a tad bland and I know it would look even better than it does now if there was some more definition in there.
Once again, this is awesome. It's a pleasure to the eye, I could stare at this for a few minutes more (and in fact, I think I will ). The armor is just amazing. I love the highlights, shading and metallic shine. Your choice of colors are good too. Love how the red, yellow, blue, blue and white go together. And not to mention the composition: it makes him look larger than life. Well done.