Screenshots

Awesome

This is gorgeous. Is this just a giant mesh, or is there some sort of level-of-detail algorithm at work?

I get what you mean. Most rooms don't use the same rocky textures in the foreground and background, like I did here. This room is a little offshoot, tucked away semi-secretly, so I wanted it to feel more like a much more enclosed space.
I've been adjusting the brightness of the background and dimmed it just a bit more. Whether it's enough of a difference for anybody to notice except me is anyone's guess, though. 

I'm not a designer at all, but as a player I honestly don't think that it blends in too much - Instead, it adds to the kind of "gloomy" feel of the room (Dark colors + not a 100% easy to discern some elements = Acts a bit like a dark room)
Not sure if I managed to say what I wanted to say, but you get me

Thanks! I've been worrying that the backgrounds might be too busy or blend too much with the more foreground tiles... been staring at these maps so long that I've become used to it, I think. I've tried dimming the backdrop even more, but I'm not sure that's really how I should be going about it. This might be a question I should ask in the forums.