One more bug I ran into: I reached the 50th floor, and immediately got a special message prompting me to face the boss. I closed the game to come back to it later. When I came back and resumed the game, the prompt for the boss encounter didn’t happen, and the 50th floor played out like a normal floor with no boss. (And I lost, so I didn’t get a chance to see if anything special would have happened if I’d found the stairs.)