The Devil’s Rain!
From the “you kind of have to watch it once” category, here’s The Devil’s Rain.
Starring William Shatner and Ernest Borgnine (!!!), The Devil’s Rain was released in 1975, and you’d never mistake it for anything other than a ’70s horror movie. It was literally and figuratively dark, dismal yet cheesy, and produced on the cheap. It even had the depressing twist ending — a real hallmark of the era.
I have seen this one, but all I really remember is the ending, which has become somewhat famous for its… erm… over-the-topness. Otherwise, this is just your run-of-the-mill “satanists secretly run the town” story, with the added bonus of Actual Satan being part of the festivities. (Not really, but Borgnine’s character came pretty close.)
It’s the kind of movie best served late at night when you’re waiting for the NyQuil to kick in.