Oh dear. This is one of those films movie critics who want to sound clever and Media Studies students love (or pretend to), and everybody else is bored and baffled by. "Legendary" sometimes means "this extraordinary film will completely knock your socks off, and even if you don't like it, you'll have to admit you were impressed", but all too often it means "this incomprehensible film will completely bewilder you, and even if you sit through the whole thing and manage to stay awake, you'll have to admit you still don't know what the point of it was supposed to be."
I'm giving it more than one star because of its ambition, its originality (this is basically a found footage movie that predates "The Blair Witch Project" by 32 years), and because to start with I was actually quite interested to see what would happen. Herein lies the big problem. Normally I wouldn't dream of revealing the ending of a film in a review, because I hate spoilers myself. But in this case it's not so much a spoiler as a warning. Nothing happens. There's no ending. The vanished man never turns up either alive or dead, the reason for his disappearance is never discovered, and not a single one of the many questions that arise is answered. The film literally ends with the director admitting they've achieved nothing and anyway the movie's about to end so they might as well all go home!
Making the central character somebody who is only shown as a still photograph was a bold move, but unfortunately he's neither interesting nor likable. In fact, he's such a schmuck that it's hard to see why anyone who wasn't his mother would particularly care about his disappearance. There's no hint of foul play (except, late in the film, a bizarre accusation from a ludicrously unreliable source), and it's established early on that it would have been perfectly in character for him to vanish simply to avoid the responsibilities of being an adult, none of which he was ever much good at coping with, so as mysteries go, it's not all that thrilling.
The most important character who actually appears in the movie is the missing man's fiancée, who has been obsessively looking for him for two years, but "The Vanishing" this ain't - not even the lousy Hollywood remake! She turns out to be such an unpleasant person that it was very likely her that he was running away from, and anyway, her quest is never concluded, because the only possible extremely vague lead they ever get quickly turns into an argument of the "Oh yes it is!" - "Oh no it isn't!" variety that chases its tail in very small circles for an incredibly repetitive and dull half an hour, at the end of which the cast and crew get as sick of it as the viewer, realize they'll never get anywhere, and give up.
If you want to see random Japanese people, nearly all of whom obviously aren't actors, improvising random stuff while pretending to recognize a photo of some bloke they're supposed to have seen a couple of years ago, shot on film whose graininess ranges from moderate to horrendous, with sound which is sometimes so poorly synchronized that a notice appears at the start informing you this not a fault on the DVD, you'll love all two hours plus of this movie! If, on the other hand, you think plotless, poorly shot films with amateur actors, and several scenes in which the director tells the cast, crew and audience that what's occurring on screen doesn't matter because it's fiction, but on the other hand, lots of Japanese people really do vanish every year and he's trying to make some sort of vague point about that while exploring the subjective nature of truth are pretentious tosh, you might not enjoy it quite so much.