I also would agree that Irreversible is a "better" film, meaning the pieces fit, the thing "works". But Enter the Void is not interested in that. As I said before, it's irrelevant wether the film "works"or not. The film is not really about the story, certainly is not really about how the main character and his sister got to tokyo, or who set him up. It's not about finding out what happened before or after. Really, being a step ahead in THAT story is useless for the experience. The film ponders basic human questions and goes to a trip inside the guy's head and soul. It's a first person "narrative" so maybe we're talking about a trip inside Noe's head and soul. How does dying feel? What happens right after? What goes through your head? What interests you? Does the circumstances of your life set you up to be a lost soul, to find something else? Paradise, God?
You see, following this guy around during this period of time is not for you to put the pieces together of the banal parts of his life...how he got into drugs, etc...I don't think those moments are there to follow that path...What you start understanding through the before, after and dream scenes are his feelings, the things within his soul that shaped his perceptions (drugs included). The character barely speaks, barely express emotions through the whole film, yet by the end you have an idea of what was happiness for him, what were his deep sorrows, what obsessed him, you understand more and more the painful closeness to his sister, and what scared him of her, and their relationship.
Void follows Irreversible stylistically and goes further with the technical stuff. As for the narrative, its' completely different in purpose. It would be dumb from Noe to just remake Irreversible in such a fashion, this is a film interested in something else. As I said, is more an exploration of unanswered questions than "the story of"...
The way it's shot is technically impeccable, as a cinephile I found myself truly levitating for a while because formally this is a film that tries to reach heights that almost no one dares to. It might be too long, but time is not everything. It is certainly not perfect, but I don't think it could be. It's too personal to achieve even something close to perfection, it carries within the strengths and weaknesses of his creator in such an "in your face" fashion that at moments it feels like a self portrait. So to me there was a lot more going on there than just the "plot".