If you loved Plastic Little: The Adventures of Captain Tita, try Legend of Lemnear
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.
What they share
Both films are directed by Kinji Yoshimoto, and they both carry the playful mood tag, and they sit in Adventure / Animation / Science Fiction territory. If that's the register that drew you to Plastic Little: The Adventures of Captain Tita, the second film will land in a comparable space — through a different lens.
playful
What Legend of Lemnear is
Red Sonja if anime. Lemnear, a legendary warrior, seeks vengeance after her village is razed by a dark lord's forces. It's an uncomplicated sword-and-sorcery quest, rendered in late-1980s style.

