The start was very strong, it reminded me much of an episode of The Twilight Zone(a paranormal TV series) or of the movie Castaway and had me very hooked. The manga got some confusing with the timelines but arguable held better than many Star Trek episodes I've watched. The timeline shifts did not feel like a gag to force action but an integral part of the piece that the story otherwise would not have worked with. Unfortunate then that the last six or so chapters were a let down, I thought Mr. Yamada would stay behind with Chika and Kamiyama with Yamada, this felt like the natural ending for the story. Worse still that Kamikaya was lost for ten years and she had a very open ending, where it is unclear if Yamada ends up marrying Chika or Kamykaya.
Of greater interest to me are the philosophical elements exploring the meaning of adulthood. In most cases they feel forced, that the manga is lecturing me about ideals rather than showing me empirical examples of adulthood. The only part I agree with is near end where Mr. Yamada explains that adults cannot just give answers to kids but rather they must discover themselves, which I think the entire survival experience Yamada had, of having to create meaning to keep living, to escape eventually, justifies this statement. If anything, I find the lectures quite annoying, that I should seemingly be grateful the great manga fed me bread crumbs of sacred knowledge. Although, this review is much longer than my other ones so I respect the manga for partly delivering on a very ambitious idea.
7/10.