Thanks to Irreversible, the notoriously graphic film that stirred up Cannes and Sundance audiences a few years ago, Gaspar Noé is already well known as a pusher of buttons and a churner of stomachs. His latest, Enter the Void, is certainly not a departure from that, but it is quite a bit more palatable, not to mention more thematically mature. From a technical standpoint, it is a marvel. From every other standpoint, it is totally jacked up. But I mean that in a good way. I think.

Noé revels in trying the viewer's patience, and Enter the Void commences its assault in the opening credits, which are set to pounding techno music and bright flashing lights, and sped up so fast they're impossible to read. It's Noé's little joke, rushing hilariously through the credits in order to leave more time for the film itself ... which is 161 minutes long and is frequently, shall we say, unhurried.

The story is about a young American man named Oscar (Nathaniel Brown) who lives in Tokyo and spends his time taking drugs. (He is able to support this habit by also selling them.) His sister, Linda (Paz de la Huerta), works at a sex club. Orphaned as young children, Oscar and Linda have had to stick together, finding surrogates to fill the emotional and other needs normally filled by parents. Oscar and Linda have a lot of issues.

Oscar's issues are complicated slightly by his death. This occurs early in the film and is foreshadowed by a conversation with a friend, Alex (Cyril Roy), about the Tibetan Book of the Dead. But death is not the end for Oscar. His spirit -- or soul, or consciousness, or ghost -- rises from his body and floats over the rest of the film, drifting from place to place, an omniscient observer of the aftermath of his death.

He also takes a trip down memory lane, death having freed him from the usual constraints of linear time. We join him in reliving past experiences -- the accident that took his parents, his and Linda's childhood, the events that happened just before the movie started -- and all of these are presented as vignettes, dreamy snippets of memory, rather than fully formed "scenes."

And I'm not kidding when I say we "join" Oscar in these experiences. We are in his head. The entire film is told from his perspective -- often literally, with the camera as his eyes, and Oscar only visible to us if he looks in a mirror. (Those shots are pretty nifty, if you think about it. How did Noé hide the camera?) In other scenes, we see the back of Oscar's head, following him around as if in a first-person-shooter video game. To show us Oscar's uninhibited floating from one place to another, the camera is positioned over the set and pointed straight down; when we arrive at the new destination, we glide down to eye level and continue to observe. In some cases, Oscar appears to float right into someone, apparently accessing their consciousness and seeing through their eyes. The effect is unsettling: I suspect that the process of dying and then wandering around as a spirit would probably look, sound, and feel like this. At any rate, it's the most effective representation of it I've ever seen.

If the film sounds like it must be visually astonishing, it is. How were these sets constructed to allow so much overhead photography? Where are the cuts being made in the shots that look continuous but must have involved multiple sets? How much digital trickery is used? Like David Fincher, Noé loves to make the camera do impossible things and access impossible locations, and it's not just to show off. In this case, it's the best possible way to make Oscar our avatar.

Also like David Fincher, Noé likes to examine the dark, distasteful sides of humanity. Enter the Void is about death, but that's the least shocking of its themes. Incest, abortion, and the sexualization of children are also on the docket, not to mention the various sleazy dynamics between pimps and hookers, dealers and users, masters and slaves. Have you ever thought about how breast-feeding is a natural and wholesome thing between mother and child, but how most adult men are also sexually aroused by breasts? Gaspar Noé has! When a man sleeps with a woman old enough to be his mother, what does it mean? Noé has some theories (as did Sophocles and Freud).

There is plenty of sex on display, some of it titillating but most of it sad or angry or hollow. This, too, is one of Noé's themes, the idea that sex can mean so many different things, can be good or bad, all depending on who's involved and what the circumstances are. (See also: the dual nature of breasts.) Some of what Noé does is insanely over the top, though I admit he does take the first-person point of view to its logical extremes. Shocking though some of the events may be, everything fits with what came before. Nothing is gratuitous, nothing comes out of nowhere.

As usual for Noé, parts of Enter the Void are hard to watch -- only it's not because they're graphic or violent but because they consist of nothing more than ethereal sound effects and trippy light displays. It's how Noé conveys Oscar's wandering mind, whether the wandering is caused by drugs or death. This sort of thing, logical though it may be in context, can be exasperating, and the film is unquestionably too long anyway. But it's a powerfully bizarre movie, a psychedelic trip that must be experienced -- not just seen and heard but experienced -- to be believed.