Update - Okay, I think I found the reason for the crash, but I don't have the fix. I tried saving after descending, and it crashes immediately. This happened 3 times. So it must be the new autosave feature that was causing the crash the other times. After the new patch, I seem to be randomly crashing on this floor.I can explore between 3-7 rooms, but then it will crash every time. I have an autosave from before descending, but even though the layout is different, I can't get any further on this floor. So far, this has happened 12 times, I'm about to try again. I haven't been lucky enough to have a staircase down to try skipping it.
I think I solved it, somehow my save had become corrupted. When I went back to an earlier save I had, I was able to save on Floor 14, and it wouldn't crash when autosaving. I'd send you the file still to see if you could find what went wrong, but I made it to Dredmor for the first time and was promptly beat down.
