Interesting info on the film, plus my evaluation
Shot in B&W, this was also known as “The Haunted and the Hunted." It was the (true) theatrical debut for writer/director Francis Ford Coppola after producer Roger Corman offered him to do a low-budget imitation of “Psycho” (1960) in Ireland with funds left over from his movie “The Young Racers,” on which Coppola worked as a sound technician. Actually, this wasn’t technically Coppola’s first film as he did eleven days shooting of Corman’s superior “The Terror” in Big Sur, California.
The story and setting are very different from “Psycho” and its sister English film “Horror Hotel” (aka “The City of the Dead”), which was produced/released at the same time as “Psycho,” although it wasn’t released in America until two years later. Nevertheless, “Dementia 13” is cut from the same B&W horror cloth and shares an infamous plot twist that originated with those two films. Like “Psycho,” there’s a psycho madmen, although he prefers an axe to a butcher knife.
Unfortunately, “Dementia 13” isn’t great like “Psycho” or formidable like “Horror Hotel,” mainly because the story is sorta befuddling, although everything’s explained at the end. There’s a good gothic ambiance, but the bewildering storytelling prevents the flick from taking off. For instance, it's never clearly established that the lake where John's body is dumped in the opening is distinct from the pond where Kathleen drowned seven years earlier. Meanwhile Luana Anders as the initial protagonist, while okay, is second rate compared to the breathtaking Venetia Stevenson in “Horror Hotel” and Janet Leigh in “Psycho.”
Corman wasn’t happy with what Coppola brought home to California. He (rightly) insisted that certain scenes needed simplified (which explains the dubiously dubbed scenes) and that more violence was necessary, to which Jack Hill was hired to shoot the additional poacher scenes. A useless prologue was also tacked on to beef-up the runtime, which wasn’t featured on the version I watched. If you’re familiar with Coppola’s later work, like “Youth Without Youth” (2007) and “Twixt” (2011), you know that he has the tendency to overcomplicate scripts. That’s the problem with “Dementia 13.” Still, it definitely upped the slasher ante and influenced that particular horror genre.