Thanks, red_kangaroo. Hard for me to say whether it looked like a GC2 ghost level or not. It had "mycelium earth" as the basic dungeon material, so maybe it was ported over from the Fungal Caves, where I died a couple of times. I've found the save game files. There's a .sav file and a .wm file for the game with the error. Should I upload them both?

I had a weird bug in GC-2 in which the up staircase on GC-2 sends me to the down staircase on the same level. The down staircase, sends me to GC-4 (not 3). I can climb back up to GC-3 and then to GC-2 via the up staircases, but then I'm back in the loop with no way to get to GC-1. Also, all enemies are now invisible. GC-2 generated as a ghost level, which may account for the weirdness, but this is still a game ender. I've gotten deeper into the Gloomy Caves before w/o this happening.

Playing in OSX Ventura. I haven't been able to find where the saved games are stored, so any pointers there welcome.