If the backgrounds were being judged seperately, you'd have it hands-down! I really like what you did with the blending on the cloud-covered moon. Great job.
I really like the background. I don't mind the outline remaining, either. the fog covered sun/moon looks outstanding.
Interesting coloring. It looks like you forgot to draw over the black outlines, the bg has no black outlines. Palette has colors very close and others very distant creating low contrast and high contrast color breaks; seems an odd choice. Plenty of colors used for bg the character would benefit from having, too.
cell shaded lineart seems novel (or lazy :P) . This looks good except the rocks which are out of perspective.
No sweet dreams for me tonight.