The pants look rather weird, lots of little folds on a rather poofy looking pantleg. I would suggest either tightening them up on his legs, or make the folds a lot bigger. Also, something of the same pants color would be good somewhere else, to balance that lighter color out a bit, it stands out a lot.
I don't really like the way his skin has the same pattern as the metal, it looks a bit dull. What if you gave him a slick, shiny surface, or scales?
The highlights along two grooves in the chest pieces look very jaggedy, as does the entire belt.
The part of the armor that covers the stomach looks like it isn't centered on his chest, it's appears to be slanting slightly to his left side (our right).
The armor curving above the shoulder could use the brightest highlight color.
I like the big metal hand, but it's a bit confusing, just how many fingers are there? When I first saw it, it looked like a normal hand, but then I looked closer and it looks like what I thought was the little finger is actually coming out of the middle of the back on the hand.
Some strong cast shadows could also add a lot of depth to this, it can be hard to just wipe out some detail you were working on because it would actually be covered by a shadow, but it's sometimes just what it needs.
It seems like the light is coming from above, why is the top of his head so dark?
I like this overall though, eager to see where you take it.