I think you've done a commendable job here adding in details and such, but some places ended up a bit cluttered. I'm looking at the legs in particular here - those parts you used make excellent armor, but the Technic bits and bobs in the back throw the proportion off, especially when contrasted with the (relatively) thin upper legs and lower torso.
Not to say they're not bad legs, per se, it's just that they look like they'd fit better on a larger MOC.
I don't really have any other critiques except about the gray joints you used. It's not so noticeable on the legs due to the armoring, but they're a tad distracting on the arms. The trans-blue you used in some of the pictures is a superior option, as it contrasts nicely with the Metru red.
Thanks for the feedback, Sumiki.
Yeah, I've been told that the legs are off. The problem with the lower legs was that I couldn't remove most of the Technic on the back without the legs falling apart... though of course I could've worked around that, so it's no excuse.
And eeeeeeeeeerrrr. People keep confusing the sand blue for grey (I should mention that in the OP). That's sand blue in the knees, ankles, "armpits" (closest approximation), and elbows; IRL it contrasted nicely, although the pictures didn't necessarily show it very well at all. Perhaps the trans blue would've been better, but I didn't have enough sockets- only six where I needed eight.
Anyway, thanks, I'll keep all that in mind.