Thanks for the critique. And about the story - when I was drawing, I was thinking of a future conflict between Earth and Mars. And this is an assassin from Earth who was sent to Mars to sabotage a plant that produces and refines fuel for spaceships.

This looks very cool! Is there a backstory to this?

One critique: your AA on the outside of the character is ineffective because it's so dark compared to the background that it just blends with the black of the character and does nothing to smooth the edge. Also, it's usually unnecessary to add a whole new colour just for AA, you can almost always use a colour from elsewhere in the piece. You can solve both of these problems by using the mid-purple from the metal parts (#7c374b) for that AA.