Good point about fishing, I hadn't thought of that. I wonder if there's anywhere in real life with an underground fish population large enough to sustain a human population... Also, insects like this ridiculously disgusting thing would most likely also be staples of their diet, particularly if they have lots of bat guano. I like the idea of a big underground lake containing geothermal vents, sounds really unusual

Mm yeah, buildings would most likely be very open plan, without as many dividers as you see irl I guess