RICHARD LINKLATER’S adaptation of Philip K. Dick’s novel, A Scanner Darkly, was considered to be a potential Cannes competition entry last year. However, this strikingly animated sci-fi film took much longer to make than expected.

This is because, as with his previous film Waking Life, Linklater works first with a cast and then painstakingly animates the film footage using rotoscope technology. It looks terrific — you can certainly see the effort that went into this production.

The main cast consists of Keanu Reeves, who plays Fred/Bob Arctor, an undercover drugs agent with a secret identity. He finds himself a little too well acquainted with the substance he is supposed to be policing, an hallucinogen called substance D, or “death” as it’s known among its users. He begins to realise that he has a problem when his psychotic roommate, brilliantly played by Robert Downey Jr, gives evidence to his undercover colleagues that implicates Arctor as a drugs kingpin.

The film’s hallucinogenic style of storytelling makes it difficult for the audience to work out what exactly is going on. The story is told through Fred/Bob’s eyes and, as we learn, he barely has one pair of functioning brain cells to rub together. The thrill from this film is in its striking look, and the deranged, trippy and extremely funny dialogue that should ensure a cult audience, if not a broader appeal among sci-fi fans.

Downey Jr is particularly good, compensating for his face being partially concealed by animation with a huge, physical performance full of windmilling arms and narcotic tics; Woody Harrelson and Winona Ryder round out the cast, which seems to have been chosen deliberately from actors with documented substance abuse problems.

This, however, is not necessarily an anti-drugs film. A Scanner Darkly is as critical of the war against drugs as it is of the substance that is turning a crime-fighting idealist into a befuddled vegetable. In the closing credits, Linklater dedicates the film to the friends he has lost or who have been harmed through drug use, but by that point the story has lost some of its initial zest and certainly its way, along with the marbles of the central character. It’s one hell of a trip, but a bit of a comedown.