These grey pieces look really nice, but the dithering looks a bit too wild :)
I second Finlal's comment.
Still, I think you nailed the overcast lighting and created an interesting scene.
Just now I found I did some mistake.
But where does the light come from?
It looks like there are at least two suns shining out there, one's rays are perpendicular to the window, and another one's - to the door.
I really like this :3 It has a neat atmosphere