I thought this documentary was a mixed bag. Some scenes are completely unnecessary and make no sense in the context of the story that is being told, while other aspects of the production are truly interesting and enlightening.

There's a lot of discussion of what goes into making a great enduring film like this, including perfectionistic direction by the overbearing Friedkin and hyper-editing (similar painstaking attention to film editing also made the original Texas Chainsaw Massacre an enduring masterpiece). Other context given is how The Exorcist was filmed on location in Georgetown, D. C. and New York City and this gave the filmmakers a lot of indie-style freedom removed from the Hollywood formula that churns out numerous mediocre movies.