Other mistake: There were no gorgons named Megara. The three that existed were Medusa, Euryale, and Stheno.
The Gorgon (1964)
1 mistake - chronological order
Directed by: Terence Fisher
Starring: Christopher Lee, Peter Cushing, Barbara Shelley, Richard Pasco
Prof. Karl Meister: Well, I hadn't seen you for some considerable time, so I thought I'd come see what you're doing.
Paul Heitz: It's a long story.
Prof. Karl Meister: I've come a long way to hear it.
Trivia: Yet another movie Peter Cushing and Sir Christopher Lee did together for Hammer Films. They'd previously done several Dracula movies, The Mummy, Frankenstein, and The Hound of the Baskervilles.