Love them or loath them here are a few comments on the Exorcist 'legacy' including the abysmal second instalment. Dominion: A Prequel to the Exorcist was directed by Paul Schrader and Exorcist: The Beginning was then directed by Renny Harlin, neither of which compare to the 1st or 3rd Exorcist. Here we have an anomaly of two Exorcist films utilising the some of the same actors, the same sets and almost the same story... this is what makes these Exorcist prequels interesting and a complete oddity.
For me Harlin's version, even though over cooked, is the slightly better film. I would suggest only watching these films out of interest and here's my comments on why.
Dominion: Prequel to the Exorcist (2005)
Father Merrin assists a team of archaeologists who unearth a church. At first, Merrin resists the idea that supernatural forces are in play but an encounter with a demon inside a boy may change his mind.

Dominion was the first shot prequel to the Exorcist, but second to be released, the story is engaging, however, I'm sorry to say that it feels like a TV movie. The script is clunky, the sets are not dressed very well and the lighting is poor. The acting is more theatre like and the lack subtle cuts make it feel a far smaller film.
Ralph Brown as Sergeant Major is very good and the opening scene of the film is certainly very effective as Merrin faces the Nazi's. Nevertheless, it does have other faults especially the CGI effects. The Dominion is interesting, but it just can't getaway from that Television look,
Exorcist: The Beginning (2004)
Father Merrin has crisis of faith after the horrific events he witnessed during World War II but when an ancient church is uncovered he must confront a supernatural evil force.
Renny Harlin's version of almost the same material, using some of the same actors and sets is far superior. The script is sharper, the sets are dressed and lit better, the acting more subtle and the use of more cuts make it a far bigger feeling film.

That's not to say it doesn't have it faults especially the effects driven finale and Ralph Brown as the Sergeant Major screen time is sadly limited in Harlin's version. Stellan SkarsgÄrd as Father Merrin is again a good choice and he's far more likable in this version. The little boy is played very well by Remy Sweeney deserves a mention.
All in all it's not a classic but the first half of the film is certainly very effective and entertaining.
Now the earlier films...
The Exorcist (1973)

I'll start by saying you could argue the film is almost over-rated. From the start the film still retains a creepy atmosphere but over the years it seems to have lost it's scare factor. That said, some scenes are still disturbing and the some foul language still amazes to be shocking.
The score, sound and editing can sometimes be a mix bag but the acting and direction by William Friedkin is exceptional. Max von Sydows limited screen time leaves an impression and Jason Miller as Father Damien Karras plays the troubled priest, however the star is rightly Linda Blair as Regan, the actress is great especially for someone so young.
There probably hasn't been a more intelligent horror film since 1973 or a better film on demonic possession. A must see for new horror fans.
Exorcist II: The Heretic (1977)

Set four years after The Exorcist Regan MacNeil is still recovering
from her previous demonic possession, but the evil may only be repressed.
As a stand alone film or sequel it's shocking and for all the wrong reasons. Maybe with another script the fantastic actors, Richard Burton and James Earl Jones to name a few wouldn't have been wasted. The music score by Ennio Morricone and some effects are possibly the films few redeeming features.
Boorman's direction is fine, but it seems the failing is in the script. It never seems to flow. Not even a good performance from Burton can save it or another edit. It's unsatisfactory telepathic melodrama.
Sorry to say it's one big miss, watch it, however, if only for curiosity.
from her previous demonic possession, but the evil may only be repressed.
As a stand alone film or sequel it's shocking and for all the wrong reasons. Maybe with another script the fantastic actors, Richard Burton and James Earl Jones to name a few wouldn't have been wasted. The music score by Ennio Morricone and some effects are possibly the films few redeeming features.
Boorman's direction is fine, but it seems the failing is in the script. It never seems to flow. Not even a good performance from Burton can save it or another edit. It's unsatisfactory telepathic melodrama.
Sorry to say it's one big miss, watch it, however, if only for curiosity.
The Exorcist III (1990)

The Exorcist film which spawned sequels and Prequels is a landmark horror film. William Peter Blatty, writer of the Exorcist novel, directs this intriguing and underrated 3rd film. Blatty ignores the messy sequel and injects some realism, horror and suspense in The Exorcist 3.
Good news for fans Jason Miller, Father Damien Karras, makes a surprise appearance. In addition to Karras the character 'Bill' Kinderman (of the original) played by Lee J. Cobb who died in 1976, is played excellently by George C. Scott. The film mostly consists of a serial killer hunt. The script is very natural and the witty rapport between Bill and the priest is fantastic, there is also a very good dream sequence.
William Blatty, considering being an inexperienced director uses some thoughtful and interesting camera angles and creates an unnerving atmosphere. This film maybe not be as shocking as other horror films but for me it has the better story line of all the series of films and is certainly worth the watch.
