I've seen lots of skinny MOCs in my day, but this one... this one has got to be the skinniest.
Granted, you could get away with that for this MOC since it is a robot. But to make that work, you've got to commit to making it feel robotic all the way through. Adding in more pistons and gears and whatnot.
Also the arms a bit too short (most human hands are located below the waist) and the colors are both boring and not spread out enough.