I saw this film when it was released in 1980 (I was 15) and i have never been so frightened in a theatre before or since. There are a number of excellent supernatural thrillers through the years, but none are as intelligent and frightening as this gem. The only one I would call it's possible equal is 1963 The Haunting.
Just my opinion :)
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Intelligent is a really great word to describe it. I'm very glad you enjoyed it. Criminally underrated is probably the best descriptor for it, actually. But yes, it's intelligent because of how the ghost story is handled. And the amount of research that went into the film turned out a story that feels so natural and real. It is really an underappreciated gem.
I envy your having seen it in theaters. I wish it could be re-released for a limited run on the big screen.
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