Caves Of Qud is a terrific sci-fi roguelike that of "effectively limitless" depth, with cryogenic clones and other treasures awaiting in the deepest places.
Sorta? If you count the first time breaking into the locked building and jumping, unassisted down the shaft “visiting” Golgotha, then i got there twice. The second time i got eaten by the conveyer belts… At least i think i did?