Revealing mistake: When Queen Elizabeth arrives in disguise, Blackadder welcomes her and is about to open the door to the closet, but you can see the door is being pushed up from the inside, probably by a crew member. (00:16:50)
Revealing mistake: When Dori types in an inquiry into the computer it is very obvious that her typing is absolutely nonsense - she types the same three letters in a row over and over again, and never presses Enter. (00:19:05)
Monster in the Playhouse - S1-E9
Revealing mistake: As the monster hops from behind the snack island, the actor's white shoes can be seen for a moment. (00:30:00)
Revealing mistake: The extras and actors are made to appear to be naked as they live in a nudist colony, but many of them are wearing some kind of undergarment.