Continuity mistake: When Blackadder, Queenie and Nursey are all comforting Melchett, there is a shot from the side view of Melchett, he is holding his head with his left hand. Then there is a shot from behind Melchett, he still has his hand on his head but when the shot returns to the side, Melchett no longer has his hand on his head.
Continuity mistake: At the very end of the episode, when it shows you all the dead bodies, you can see Queenie to the right for a few seconds. The dagger she is holding is pointing upwards. Then there is a close-up of Queenie, who then talks back to you in Prince Ludwig's voice, and the dagger she is holding is now pointing downwards.
Continuity mistake: "Blackadder Back and Fourth": Blackadder and his guests are going down stairs. Blackadder is first, George is second, Melchett is third, Elizabeth is fourth and Darling is fifth. Blackadder gives his notebook to George. When they arrive downstairs, Melchett and Elizabeth are ahead of George. This is not logical, since the stairs are too narrow and they could not have passed George.