Thanks Meshon,

I took your advice and dirtied up the floor a bit more with textures and Photoshop filters rather than objects since the .psd file was already almost 600mb. I also cleaned up some of the debris piles they had too much stroke on them and looked bad.

I forgot to mention in the initial post that I made the map entirely in Photoshop CS6 using layer masks for the floors/walls/lava/lake. And then I took some boulder objects I had that looked suitably organic. I added black shadowed doorways and smoke holes, then added some mushroom growths on rooftops. I made a few variations and these became the rockshaped buildings. The grasses on the shorelines are a stock Photoshop brush to which I added highlights/midtones/shadows coloration.