"The Exorcist" by Yojimbo
I have only just seen this film (to my shame!) and I must admit, I was disappointed. I can only assume that the constant barrage of copycats and parodies that followed have removed any surprises, as I wasn't remotely scared or even shocked by any of it (in fact I found the exorcism sequence rather laughable). It's merely a nicely shot theological thriller with brief bursts of violence and foul language, and a story containing a series of seemingly unrelated plot threads that do not tie together satisfactorily (if at all). Oh well...