Factual error: At the climax of the movie, Alice swings the machete at Mrs. Voorhees and decapitates her. When the blade makes contact with Mrs. Voorhees' neck, her head flies off at an incorrect angle, as though the cut began on the opposite side.
Factual error: The first thing on screen after the opening credits is the year the film is set in, 1953. How then, do Kim Novak and Tony Curtis make their arrival in a Cadillac convertible, which is quite obviously of 1959 vintage? (00:19:44)
Factual error: A solid gold cross of the size used in the film would weigh more than what any human could hold in front of them (nearly 200kg), much less as "easily" as the priest did at the end of the movie.