If you loved Sea Prince and the Fire Child, try Super Mario Brothers: Great Mission to Rescue Princess Peach
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

Sea Prince and the Fire Child
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Super Mario Brothers: Great Mission to Rescue Princess Peach
What they share
Both films are directed by Masami Hata, and they both carry the playful mood tag, and they sit in Animation / Fantasy territory. If that's the register that drew you to Sea Prince and the Fire Child, the second film will land in a comparable space — through a different lens.
playful
What Super Mario Brothers: Great Mission to Rescue Princess Peach is
A theme-park mascot’s side hustle momentarily escalates into high-stakes heroism. Plumber siblings trade wrenches for warp pipes in a kingdom of talking fungi. The entire journey unfolds on a single mushroom-shaped set.