Sounds a lot like the novel Chthon by Piers Anthony. Any influence there?
Funnily enough — no. I actually heard about the novel after I released Cthon, and have been meaning to read it ever since but haven’t gotten around to it. The concept of mines beneath a planet surface is eerily similar to the game though. The title Cthon was a reference to the Greek term of being “of or under the earth”, and fit well as the game uses a lot of concepts from an earlier unreleased rogue-like game I toyed with for a while about delving an ancient Greek necropolis, except Cthon sets things in the far future.