Is Puchitto Gargantia hentai?
No
Rated PG-13 (Teens 13 or older) on MyAnimeList and not tagged as Hentai.

ONA · 2013 · 13 episodes · PG-13 - Teens 13 or older
Mecha, Sci-Fi
Short episodes streamed on the anime's official site after every episode, giving background information about the show.
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