Just rewatched this and decided to look for some discussion about the movie...
And tis true
. Hiroki in the intro definitely looks much older than the end of the movie. The face is longer and has the more angular lines of an adult. The intro also has a quick scene of him passing by (stopping by?) a graveyard. And the tower is missing from the view of the sky. So in the end, chronologically, this is yet another Shinkai bittersweet ending.
The optimist in me will probably say that the adult Hiroki is visiting that area on some government business and Sayuri is happily waiting for him at home
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