One of these days, Gaspar Noé is going to make a perfectly quaint little romcom - and the surprise will kill us all. Until then, he is set on a more conventionally shocking path, conducting experiments in sensory overload.

Despite its unrelenting grimness, his 1998 debut, Seul contre tous, understood the tease of the tawdry as well as any Roger Corman B-movie. Before an outbreak of violence on-screen, a message in red letters flashed up, warning us that we had 20 seconds to leave the cinema. Clanging alarm bells made the coup de théâtre complete.

Noé's new picture, Enter the Void, is another endurance test but for unusual reasons. Harder to bear than the gory violence and explicit sex, or the stroboscopic credits sequence designed to weed out any epileptics, is the irresolvable tension between the avant-garde provocateur Noé wants to be and the narrative traditionalist he really is.

Oscar (Nathaniel Brown) and Linda (Paz de la Huerta) are orphaned siblings living in a neon-scarred, nocturnal Tokyo. He's a drug dealer who isn't averse to getting high on his own supply; she's a stripper who doesn't stop being a commodity when she clocks off. Clearly, neither of them has addressed properly that tricky work-life balance.

But at least Oscar has stayed true to his promise to Linda that he would never leave her. OK, so he encouraged her to come to Tokyo, introduced her to drugs and didn't do more than grumble when she fell in with some unsavoury types - but let's not nit-pick.

He's such a devoted brother that even being shot and killed doesn't stop him from keeping an eye on her. As Oscar's body lies curled and cold in a shower cubicle, his spirit drifts over Tokyo, waiting for the emergence of a new life through which he can return to earth. It's all laid out in the handbook otherwise known as The Tibetan Book of the Dead, a copy of which Oscar was consulting before his death, in the manner of a motorist logging on to Google Maps.

His demise may have resulted from being in the wrong place at the wrong time, but, when he's in spirit form, his command of narrative priorities and his ability to be present for any encounter needed to further the plot suggest that he's also been swotting up on Robert McKee's screenwriting manual, Story. Oscar witnesses the comeuppance of the friend who betrayed him and never misses an instalment of his sister's ongoing degradation. His tastes as a ghost run to the soapy: he drops in on Linda's lover just in time to find him having sex with another woman. And he's there to float through a brothel where the joyless grinding corroborates Noé's view of humanity as a seething cesspit. Oscar's knack for being in on every critical moment doesn't feel like omniscience so much as organisational excellence on his part.

Enter the Void is shot with a subjective camera and Noé is even careful to replicate Oscar's blinking (at least while he's alive - ghosts
don't have eyelids, silly). Only the flashback sequences, during which the camera is positioned behind Oscar, are exempt. These provide another example of the striking respect for narrative coherence that apparently comes with death. Oscar collates every piece of in­formation necessary for us to assemble his complete backstory. If it's a harrowing memory, such as his parents' death, he helpfully replays it several times over. You can never see bodies crushed in a head-on collision too many times, that's what I say.

Noé's intention to make a 2001: a Space Odyssey for a new generation is advertised by his picture's cosmically inclined themes and some psychedelic special effects that run the gamut from A to LSD. An extended acid-trip sequence is pleasant enough, even if the same effect could be achieved by drinking too much cough syrup and staring at a lava lamp.

But for all its visual eclecticism, Enter the Void has the profundity of a gap-year chinwag on a beach in Goa. Its view of life and death is so comforting and literal-minded, cinematically and philosophically, that it's less a new 2001 and more like an art-house Ghost.

Ryan Gilbey blogs on film every Tuesday at Cultural Capital