No discussiion of horror/sci-fi would be complete without at least one William Castle film. His opus "The Tingler" was campy and weird but sent dozens screaming from the theatre. OK, so some were paid to scream and fake a fainting spell, and some were helped by vibrators under the theatre seats, but the movie was a great success.
I remember going to the movies and seeing his gender/bender "Homicidal" . Couldn't sleep for several nights. Great stuff.