I like the overall design of the suit and it's taking on the beginnings of looking like metal.

First thing that stood out out for me was that there was no color! Adding color would take it to the next level of looking more like real metal. First thing I would do is gather tons of reference images for armor. You will notice when looking at those images is that the metal has color...whether it's color from the metal itself, reflected, or warm/cool lighting. You can also add color using decorative details like gold inlay, etc.
I might add details like how the suit is held together...screws, straps, etc...to "sell" it a bit more. As far as the background goes, he seems to be floating right now, he needs to be grounded to something. Adding a simple shadow will work.

Looking forward to the update!