`In The Mouth of Madness' is probably Carpenter's last great film, but it's definitely not an unqualified success: uneven and inconsistent, it is saved by some wonderfully atmospheric sections that make up for the weaker elements in the movie.
Sam Neill is John Trent, a fraud investigator sent to investigate the disappearance of Stephen King-a-like Sutter Cane (Jurgen Prochnow), a man whose horror novels are having a disquieting effect on the psyche of the world. Tracking him down to a town that shouldn't exist, Trent is plunged into a maelstrom of evil from which there may just be no escape.
First, the weaker points. The first half of the film is not fast-paced, but instead of a slow-burn build up of tension and menace, contains one or two fairly cheap shocks and hammy moments. The framing sequence with Neill in an asylum is probably the weakest part of the movie, hampered by Neill's inability to act convincingly insane or dangerous. He's much better as the urbane cynic he portrays for the bulk of the film, but even then I can't help feeling there must have been actors more suited to the role than him. In fact, the acting in general is not the film's strong point: Carpenter refers to this as the third part of an `Apocalypse' trilogy begat by `The Thing' and continued with `Prince of Darkness', but doesn't have access here to the compelling, intense cast of the former nor the endearing oddball players of the latter. Julie Carmen is fairly insipid as Neill's sidekick (though her character does get one of the best and most literally twisted scenes in the film) and Jurgen Prochnow is merely passable as the author who now does the bidding of Great Old Ones. (The exception is the always-wonderful David Warner, though he is rather underused, with a fairly minor part.)
But... at round about the halfway mark, the film starts to turn into something special. In fact, the exact moment is pretty easy to pinpoint. It's when Neill encounters his landlady in her `real' form that the movie kicks into high gear and really starts to become disturbing (in the best possible way.) Indeed, the sequence in which Neill flees the hotel while blasphemous abominations start to emerge is irresistibly reminiscent of what for me remains the most terrifying moment in Fulci's equally Lovecraftian `The Beyond': Lisa's flight from her own hotel and the appearance of shambling shadows at each of the windows. Neill's frantic and futile attempts to escape the fictitious town in which he is trapped becomes the stuff of explicitly Cthulhoid nightmare, culminating eventually in a sequence in which Neill is pursued by ungodly horrors (is that Shub-Niggurath?) just as unpleasant as any of the Thing's manifestations. And given that I regard `The Thing' as one of the greatest horror films of all time, that's high praise indeed.
The DVD itself is strong: the picture looks great and there's a Carpenter commentary, though maybe not his most enthralling. Overall though, this is definite must-have, despite its faults, though probably not the best starting point for a Carpenter virgin: it strikes me as very much a film for the Carpenter fan.
(And on a random note, I can't help but feel that video game `Condemned 2' owes this film rather a lot.)