What I find fascinating is that if we can assume that the extent of the dungeon key are the notes at the top and the bottom, how much of it is empty and/or random-encounter to populate.
It's a design theory that's dwindled as the game has evolved, but early dungeons (see also Tegel Manor) were often definitely designed to be mazes to challenge the players, in addition to all the monsters and traps to challenge the characters.