Secret passageways, creeping stalkers prowling at night, love triangles complicating relationships like guys and gals had nothing else to do, and intrepid women reporters, tough as nails, always screaming on cue. Ah, the early days of mystery and intrigue. Oh, and toss in that crazy scientist conducting brain experiments (which was a scripting go-to back then for some reason), a “Thing” kidnapping that spunky reporter (through those convenient sliding panel beckoning hidden passageways), and that close-by sanitarium as the main hideout. Don’t you also miss those days of naming actors with catchy nicknames like “Big Boy” Williams in the credits? I don’t recall women ever getting nifty nicknames, do you?
One more thing (no, not that Thing). I mention The Phantom because it is recognized as having influenced the horror genre and was an early independent film (Artclass Pictures Corp.) with horror elements. (See The Phantom (1931): Hollywood’s First Independent Horror Movie for a critical analysis.)