The Nightmare

While there is a well-maintained sense of lurking discomfort, the gotcha scenes feel a little cheap.

It just isn't as informative as it could be. It's plenty scary, and on that level satisfying. It would be great to see Ascher make a full-on horror feature.

In the faces of these men and women, ranging in age from their 20s to their 40s and spread out everywhere from Los Angeles to Manchester, you can see the genuine terror they suffered - and, in some cases, continue to suffer.

Ascher plunges us into the actual visions that sleep paralysis creates: the moving silhouette figures, the darkness, the static. The sense of terror is palpable.

Ascher is too content to let repetition of experience take over his film. No sleep studiers or brain experts or anybody else, for that matter, are interviewed.

While "Room 237" sought evidence for its most outlandish conceits, "The Nightmare" declines to delve. As the testimonies grow repetitive, the strategy suggests willful ignorance.

The Nightmare squanders [its] subject in a shallow, messy and frustrating documentary that tends towards the pseudo-intellectual and paranoid.

An intriguing feature, but one that ends up dulling your senses with repetitive talking heads and recreated scenarios.

The Nightmare is a completely singular work of documentary, unseen before to this degree of craftsmanship.

Both the re-creations and the interviews themselves are filmed for maximum spookiness.

It's compelling viewing, as well as disturbing as hell. Honestly, who needs the spectres of Insidious: Chapter 3 when our own brains are capable of scaring us half to death.