Cralon

Cralon is "an authentic 3D dungeon crawler with RPG and adventure elements" about a demon hunter who falls into an old mine and must find his way out—which, in the way of these things, means going deeper. Naturally, there's some bad stuff hiding in the depths of the delve, and you're going to have to get that sorted, with some help from "the creatures of the shaft," before you make your escape.