Well if you noticed whats wrong, I don't know what to say then lol. Hopefully something I mention can help you unless you thought about it already. Very first thing I noticed was the right arm length. The arm seems to be small in length at the moment. The character looks to have no trapizeus muscle. Adding a bit more definition could help. Not much needed though. The left leg is another area that I believe needs to be reworked. Just like the right arm, the leg is too small. As far as colors go, I feel as if the character is a bit to monochromatic at the moment; which isn't a bad thing if you want it that way. The Sky light is just that, a sky light to help define forms more, but the suit can have a bit more color to it. Adding in some secondary colors and some accent colors for lights, trims an maybe some warning signs for the hot areas on the helmet can help. Giving color to different areas of the suit can help it pop more an seem more vibrant as well. So I did a paint over on things I would do as well as showing a example color palette. It's kinda crap and you can probably make it better to fit the character more. I reworked some areas of the anatomy as well as some of the forms. As for the anatomy your rib cage seemed a bit small so I made it a bit bigger but this was a personal choice. Yours is fine an can be kept the way it is in my opinion. I was aiming for a little more realism but you always have a cool style to you figures which I like. When it comes to shading the forms on a character I try to think of it as a simple shape. I like to draw a visual of the basic form next to my character or object so I can better understand it. That's why the sphere is there. I needed an example for how the shoulders and boob area would work. I really like the lines going on in the helmet design as well as the helmet shape. Keep up the good work as always. Use as much reference as you can for the anatomy stuff. This a really cool character. Hope you can take it to final.
I forgot to do bounce light, but that's something you also want to remember to add in to show the forms of the character better as well. My left leg is probably still to short so you can fix that when you tackle this character again. 
Hope this helps.
Cheers!
