I first discovered this movie about 15 years ago when it ran on a rainy Saturday afternoon throwaway slot. This isn't a great movie, but it's a great potboiler, where even if you know how it's going to end, you like watching the characters unravel throughout the story. Camp at its best.
You don't see movies like this anymore, probably because they don't use self-conscious ironic detachment. The (over)acting must be good enough that the players actually inhabit their roles. Play it straight and it's unwatchable. The effects aren't so special, so it's just as well that the action is implicit rather than graphic.
Everything about the film is dated--there's no mistaking the costumes or the music for any era other than the mid 70's. For that matter, the voiceover, the ticking clock and the freeze-frame shots of the characters probably looked dated even when the movie was new. But that's not necessarily a bad thing. Later the horror film evolved into the mindless slasher film in the late-70's-early 80's, where the killer was only a setpiece, and then into the 90's, where the ironic, self-aware Scream type picture cannibalized the former genre. So hungry were moviegoers for subtle, sincere horror that they drooled over Blair Witch. It was a valiant effort, the spookfest had all been done better, when films relied on pacing, acting and camera angle to scare the audience instead of gore.
It's surprising enough that this film merited a DVD release at all and I was so thankful to find it that I didn't even care about the lack of outtakes and extra comments. The next rainy Saturday afternoon I'm watching this again.