I wish I could have documented this bug better for the developer but i will just describe it

twice I walked through walls. One time it was just one character(the death knight) one time it was both characters.

Both characters walked through the wall at around the area where the lever is that opens the first prison area.

My characters walked through the black area around the whole perimeter.

I couldnt get back in the fortress. so it was game ending although i could walk around a large area of blackness.

Antoher time the death knight walked through a locked door and fought the ghost inside. after he killed it we unlocked the door but if i didnt have the key my characters would have been seperated at least til i found the key.