Richard Linklater's CV as a director is, to say the least, varied. We've had the spoof documentary 'Slacker'; the nostalgic cool of 'Dazed & Confused'; the growing pains of 'Suburbia'; the fun of 'School of Rock' and 'Bad News Bears'; darker fare like 'Waking Life' and 'Tape'; and, in 'Before Sunrise' and 'Before Sunset', two of the best love stories to make it to the screen in the last two decades.

So Linklater's decision to film author Philip K Dick's ('Blade Runner', 'Total Recall', 'Minority Report') novel 'A Scanner Darkly' may seem like another unusual choice. Look a little closer, however, and it doesn't seem so strange: many of Linklater's films involve people on the fringes of society - and people who like to do a lot of talking. Sadly, while 'A Scanner Darkly' is a technical triumph it also feels quite pointless.

Using the same rotoscoping (digitally painting over live action footage) that he debuted in 'Waking Life', Linklater tells the story of Bob Arctor (Reeves), an undercover officer who himself is addicted to Substance D, the powerful drug which seven years into the future has 20% of the population hooked.

Arctor lives with stoners Barris and Luckman (Downey Jr  and Harrelson), hangs out with dealer Donna (Ryder) and actually oversees the police surveillance of his own home, thanks to an undercover device called a 'scramble suit', which means that Arctor's superiors don't know what he really looks like.

With his hold on reality getting ever shakier, Arctor doesn't have anyone to turn to for help. He's a pawn in a game, but just how big is the game?

Undoubtedly there will be those that reckon 'A Scanner Darkly' deserves to be ranked alongside 'Drugstore Cowboy', 'Trainspotting' and 'Requiem for a Dream', but for others, once the novelty of the animation has worn off, it will prove to be a slog.

The film's problems are numerous. There is too much dialogue and too little of it is meaningful. There's no bond with any of the characters so you don't care what happens to any of them. And the animation doesn't enhance the story at all - more time should have been spent on the script and less on the effects.

The points 'A Scanner Darkly' is trying to make about government intrusion, paranoia, hypocrisy and isolation in society have all been made far better in other films and here come across as clunky and heavy-handed. Ultimately, you'd get the same level of insight and stimulation from the closing stages of a student party in Rathmines.

Harry Guerin