If you loved 20th Century Boys: Beginning of the End, try 20th Century Boys 2: The Last Hope
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.
You already loved

20th Century Boys: Beginning of the End
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20th Century Boys 2: The Last Hope
What they share
Both films are directed by Yukihiko Tsutsumi, and they sit in Adventure / Mystery / Science Fiction territory. If that's the register that drew you to 20th Century Boys: Beginning of the End, the second film will land in a comparable space — through a different lens.
What 20th Century Boys 2: The Last Hope is
Rain taps a rusted playground swing in winter twilight. A girl traces coded marks on a bunker wall, while fugitives gather around a dying man’s notebook. Like a Japanese *Children of Men* made by a shonen manga fan, it turns paranoia into prophecy.