It's beautiful work. The thing I'm worried about is that it's so detailed and has such high contrast that it is too busy for a background element. In the mockup with objects in the room, they barely stand out against the texture of the walls. If you think about the relative hierarchy of visual interest and where you want the player's eye to go, the texture of the walls shouldn't be very high on the list. Perhaps something more subtle is in order?
I'm reminded of this post from the Witness blog about rocks. It's obviously very different from the style you're going for, but you might take away something valuable from it.
http://the-witness.net/news/2013/09/on-the-rocks/Thanks Dave, its a good point. I'm trying to keep the colors fairly desaturated so I don't compete with the character, but I probably need to dial down the contrast too. Instead of deep, dark cracks I can fill them in with a suggestion of built up dirt. I definitely want the character and the effects to be the focus.
I also plan to add a shadow layer which will help ground the objects in the environments.
Thank you for the link, bookmarked.
Update, first pass based on Dave's advice. I think I can push the contrast down even more. Added a quick and dirty shadow under the objects to ground them.
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