I love the colours in this one, but the fire in the "fire cage" (or whatever you want to call them) doesn't make much sense in terms of how it's illustrated, and the fire cage implemented in the gun-blade looks to be drawn in a hurry compared to everything else.
Aside from that, I really love the design of this character. The distribution of colours in the picture help with leading the eyes. The face is devoid of much colour save from the eyes, and when you look down, the colours get more powerful as you get close to the hip area and mechanical hand.