Seeing the Exorcist again now after nearly 30 years, I'm struck by how it stands out from its genre. Friedkin had already shown himself to be a master of characterisation and ambiguity with the extraordinary French Connection, and the Exorcist is definitely as good. The scenes between Karras and his mother are beautifully and subtly scripted, as are J Lee Cobb's scenes. Maybe the shock value of the possession scenes has faded a bit over the years, but the encephalogram scene is still incredibly powerful and affecting, showing the terrible ordeal Regan has to go through. Friedkin's commentary track is a bit disappointing, being little more than a step outline, but it is nonetheless interesting to hear his very personal confession of faith.
Horror movies (and genre movies in general) are fascinating when they step outside of the boundaries set by their genre, and the Exorcist - probably because it was written by the novelist himself - shows a depth of characterisation that few horror movies ever reach or even attempt to. Compared to the rash of stereotyped and unimaginative exorcism movies in recent years, the Exorcist has lost none of its power and stands head and shoulders above the rest of the crop. You don't have to like the horror genre to appreciate and be moved by Regan's suffering and her mother's desperation, and, for me at least, this is what the movie is about.