The books of Philip K Dick are an acquired taste, and this apparently faithful adaptation of his 1977 novel by Richard Linklater is hardly likely to reach beyond the status of a cult movie.

If the author doesn't put a mainstream audience off, the use of rotoscoping might, which transforms the live action into animation by handtracing each frame of the film.

So, we see an admittedly skilful approximation of Keanu Reeves as Bob Arctor, the undercover cop whose mind is being destroyed by the drug Substance D like almost everybody else's in this world of the not-too-distant future.

He's under surveillance by government operatives, along with his two housemates, Robert Downey Jr's Barris and Woody Harrelson's Luckman, and his drug-dealing girl, Donna (Winona Ryder).

Unlike in Ridley Scott's Blade Runner or Spielberg's Minority Report, there's no attempt here to massage Dick's skewed message, born of his own addictions, that drug culture will sooner or later take hold of the world whatever governments do to prevent it.

The supposition is, too, that those who lead us are likely to be up to no good, and conspiracy theories come and go bewilderingly throughout the story.

Linklater also used rotoscoping in his last movie, Waking Life. But whereas that film was made up of existential conversations, this has much more plot.

It is essentially a detective story whose characters are mostly drugged up and it starts scarily with Rory Cochrane's substance-affected detective trying to rub aphids off his skin. We don't know whether it's psychosis or reality, and that sets the tone for the rest of the film.

If it's a nightmare vision of the future that we've seen before, at least it tries for a style that's comparatively new and audacious.

It works well at times, such as when a surveillance officer's face morphs into a dozen different characters as he addresses a conference on the lengths the government is prepared to go to stamp out the terrors of Substance D.

His enthusiastic audience applauds him, only to witness him losing his way during the patriotic bit of his speech, probably because he is as drugged as those he's supposed to investigate.

But the film suffers from a lack of real emotional involvement. We watch, intrigued at first as to where it's going, but we're gradually distanced by the methods employed.

Despite the clever technique, and a screenplay that is mostly free of obvious cliché, A Scanner Darkly remains an experiment unlikely to be repeated if its poor box-office returns in America are anything to go by.