The Exorcist (1973, William Friedkin) was a huge sensation when released - it was banned in places, discussed in talk shows and the media, and walked out on. It came along at a time when big theological questions were in the public eye, and as such almost inadvertently became a sensationalist phenomenon that was concerned with Big Issues. It is of course an entirely fabulous film, still riveting after all this time. Hollywood wasn't as prone to sequels back then, but the huge success, both artistically and commercially, of The Godfather II in 1974 had proved that a sequel needn't mean cheapening the storyline. And so in due course along came Exorcist II: The Heretic (1977, John Boorman) with Linda Blair joined by great actor/ham combos such as Richard Burton and Louise Fletcher. It was a troubled production that was fitfully released, hauled back to the edit suite, and finally abandoned by both Warner Bros and the director and dumped into theatres to the jeering of the crowds. The Razzies hadn't been invented then but you can be sure Exorcist II would have been a contender.
1983 saw the publication of William Peter Blatty's follow up to his original novel, Legion. It's weighty, meditative, and theological, and when production company Morgan Creek allowed Blatty to write and direct an adaptation for them, it should have come as no surprise that he delivered a weighty, meditative, and theological film. Shocked to discover - after the film was completed - that Legion did not contain any sequences of exorcism, Morgan Creek insisted on having one shot for the film. Although Blatty disagreed, he was a good enough sport to shoot the new sequences, hoping to still do the best job possible. The film, The Exorcist III: Legion (1990) is creepy and well made and leaves an impression despite the completely visible join between Blatty's story and the studio imposed exorcism. And it has one of the best shock scare moments of the last couple of decades.
The final sequel to date had the most torturous post production of all - fearing Paul Schrader's film Dominion: Prequel to the Exorcist would be unsuccessful, Morgan Creek hired director Renny Harlin to completely reshoot the film. Harlin's Exorcist: The Beginning was released to poor box office and negative reviews in 2004, and Schrader's film was eventually released as well in 2005, to a slightly better reaction.
Has there ever been a cinematic franchise with such a troubled production history? The fourth film especially being completely reshot, never mind Paul Schrader - a promising match for the material - being dumped in favour of Renny Harlin, of all people. A clear sign that the studio really had no idea what sort of film they really wanted.
Of course, the original film has not been without after the fact tinkering either. In this case, a long standing dispute between author/screenwriter William Peter Blatty and director William Friedkin was re-ignited when the film was re-released for a short theatrical run and then on DVD for its 25th anniversary. At that time Friedkin stood his ground, but a couple of years later he relented and the ridiculously yclept The Exorcist: The Version You've Never Seen was released in 2000. The new version re-instates some character material which Blatty had always missed, as well as the infamous "spider walk" scene which doesn't really fit - coming before the film has taken its shocks to that kind of level, it both steals the thunder from later scenes and disrupts the slow build of tension. Freidkin also adds a couple of ill-advised new visual effects, particularly an image of the demon's face appearing in the range-hood which is completely meaningless within the story. It ultimately doesn't matter, it's still pretty much the same film, and some of the extended sequences help what seem like big narrative leaps in the shorter version. My preference, however, is definitely for the original version, although truth be told, you can't even get that these days: the closest being the first (now out of circulation) DVD release, which replaces the startling and effective jump cut from Jason Miller playing Father Karras to the same actor in demon makeup with a more subtle digital morph, but is otherwise the same as the 1973 release.