Septike: Hi,
sometimes I cannot finish a dungeon but exiting usually solves the problem, though the time playing the dungeon is lost.
If not, swapping characters solved the problem till now.
Yann_Darko: Thanks, it seems quite manageable... if this bug doesn't happen too often.
It happens mostly when you fight in the narrow doorways. When you do sometimes the doorway is still blocked after you killed an enemy. If it is the only entry to the room, you can't complete the dungeon and have to start a new one.
Besides that I also encountered a graphical bug a few times (perspective glitched out and got very weird), but that's not game breaking (it will be gone after you've completed the dungeon).
When I played last year also the Galaxy achievement were broken (every unlocked one popped up again when you played the first dungeon of a session). That was annoying but I guess you can't blame the developer for it (seemed to be on GOG's side).
Besides that I don't recall any major bugs and I've played more than 120 hours last year.