I've also got stair issues - needed to go back to level 1 to use the only shop so far. No stairs on level 2 go up anymore. If I load the autosave, I can't go back downstairs either, but if I load the save I made, I can go back down. The crashed when I first went downstairs from level 2 to 3, then I loaded from an autosave and continued. I tried out the hotfix, but lost all access to my subscribed mods (I'm using the Steam version of Dredmor). Had to revalidate and redownload to get mods back. Tried to attach my saves, but both the autosave folder and my current character folder are >3MB each after compression and wouldn't upload. Both the autosave and current save are missing all level.dat files above level 2.