While not denying the criticisms leveled by other reviewers, I found a resonance in this movie that transcends the narrow framework on which it is set, the economic challenges of Japan in the 1960's.
The situation has been fairly well laid out--five friends, drawn together in a dream of hope for the future in a heartless city, the weak are weeded out, the two who succeed find no happiness.
But the film is not about the story of a dream deferred, it is the story of the individuals. Each of these characters is defined not by what they are striving for together, although that is the one thing they share in common, but by the weaknesses in their characters, the baggage they have brought with them from childhood, that have made them who they are and conspire to defeat their goals. One was traumatized by his mother's promiscuity, which creates an insurmountable barrier in forming intimate relationships; one was twisted by his insecurities into becoming a chronic liar and vicious coward. These characters rage more against their personal demons that betray them at every turn more than they are fighting against society.
They want to fit in, to form loving families, to trust and sustain their friends, but they end up betraying one another. It would be accidental if it weren't consciously decided upon, and even they are unable to articulate why they must behave as they do. Their own confusion is translated to the audience, and the cinematography contributes to this.
There is a bleakness to the film despite the vivid colors, but at the same time there is a sense that the surviving characters have not given up hope for the future, and the final message in this film is the same as in "Battle Royale"--Run for all you're worth. Run!