If you loved The Adventures of Milo and Otis, try Little Nemo: Adventures in Slumberland
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

The Adventures of Milo and Otis
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Little Nemo: Adventures in Slumberland
What they share
Both films are directed by Masanori Hata, and they both carry the cozy mood tag, and they sit in Adventure / Family territory. If that's the register that drew you to The Adventures of Milo and Otis, the second film will land in a comparable space — through a different lens.
cozy
What Little Nemo: Adventures in Slumberland is
Here's a film that likely seemed like a good idea at the time. Young Nemo is invited to Slumberland by King Morpheus, only to unleash the Nightmare and endanger everyone. It's a kid's film that probably scared a lot of kids.