Interesting concept. He looks like a possessed suit of armour. You've got a great eye for values.
Not sure about the illustration composition you chose though. From the four thumbnails sketches you made, the bottom 2 compositions were more striking to me. The one you picked doesn't have the same oomph, mainly because of the character's uninteresting pose.
It's rendered very nicely though! I'd hate to say "redo" your hard work, so take what I say with a grain of salt. Others might disagree with me.
