Crew or equipment visible: When the fanatics parade through the village, rolling a huge wooden wheel before them, a stack of camera equipment, partially covered with a blanket, can be seen in the background.
Crew or equipment visible: During the fight in the quarry near the end of the film, there is a shot of a knight falling of his horse; the side of a white prop truck is clearly visible behind him.
Revealing mistakes: Wires can be seen holding up the head of the monster at the end of the film.
Anachronisms: Potatoes, whose origin is the Andes mountains in South America, were not known in Europe before about the middle of the 16th century and hadn't became staple food until mid 17th century - i.e. well after the feudal knight era of the movie.
Anachronisms: In the Princess' nude scene, she obviously has modern tan lines.