The idea is there. Its symbolism for a war machine to be holding up a human's dwelling and holding a aerial ballistic towards itself is a nice idea. Like the robot wants to change from its wartime industrial mindset. That being said.
I thought the aerial bomb was his other leg for a really long time until I realized that it was an aerial bomb. And its a little phallic. Actually It's really phallic. It's a peepee. Maybe if it was shaped more like a V2 rocket it would be better.
The story seems "extremely barren wasteland". If they are regrowing right after the war this is more the feel you have with the grey and snow. If the robot was hidden amongst a green and luscious forest then I could see it being a nice surprise in the illustration when i the viewer discover the robot. But that might not be your intent.
And to be nitpicky, as a designer.....
How do I the human do maintenance on the windmill?
Why do I spend so much energy gathering water to do laundry at my house?
Wouldnt' I just do it by the creek?
Do I walk precariously on the arm from my house on top of robot when I need to?
How do I get up on top of the robot when I need to?
Why am I living on the hand and not the top of the head or using the metal of the robot as shelter?
Why would I live at this robot with an un-detonated aerial ballistic?
There has to be some other robot surely?
Why do I live up high am I hiding from predators? That's pretty dangerous with no railing.
Why wouldn't I just use one of those trees or be on the ground like humans did for thousands of years?
My point is there has to be a benefit I'm not seeing yet for re-use of the robot carcass. I would totally live in it if it provided shelter and stuff. It makes me smile to think about if at night the eyes and armor holes were lit up with the abundance and happiness of human life, in contrast to the opposite of the cold death that it represented in its days of industrial war. If you think about adding even more humans and doing a small village then I have more things to look at to not make me ask all those questions. It makes my animal primate brain think, "oh all these other humans are doing it so it must be okay. or have a benefit. Can I join them and benefit?" Its like the megaton city in fallout 3 remember?
Anyway food for thought i hope you post the finish!