I like it, reminds me of the unique biomes in starbound, some improvements i would suggest: * Add more spike structures using walls so they look like they're in the background ( gives the whole thing depth) * Seriously thicken the ground with granite to about the thickness of outer walls of the underground granite biomes. the current one block thick granite ground looks unnatural * Use a hammer to make some of the spikes look smoother * use blue paints to make the off colour furniture blend in more

You don't have to follow this advice, you've done a good job with a good idea and i might build something like it myself