If you loved Phineas and Ferb The Movie: Across the 2nd Dimension, try Phineas and Ferb the Movie: Candace Against the Universe
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

Phineas and Ferb The Movie: Across the 2nd Dimension
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Phineas and Ferb the Movie: Candace Against the Universe
What they share
Both films are directed by Dan Povenmire, and they both carry the cozy, mindfuck mood tags, and they sit in Animation / Comedy / Family / Science Fiction territory. If that's the register that drew you to Phineas and Ferb The Movie: Across the 2nd Dimension, the second film will land in a comparable space — through a different lens.
cozymindfuck
What Phineas and Ferb the Movie: Candace Against the Universe is
Here's a film pitched squarely at those who know precisely who these characters are. Candace is kidnapped by aliens and whisked away to a distant planet. Her brothers embark on an intergalactic rescue mission. It's probably canon for someone.