Leda: The Fantastic Adventure of Yohko (1985) IMDb
Seen in 2016.
An “ordinary” high school girl has made her own musical composition, with a novel melody. It’s in her headphones when she tries to work up the courage to ask a boy out. It doesn’t work. She falls into a fantasy world.
An effective treatment of secondary-world fantasy as an extended metaphor of the personal maturation process. That whole concept is fundamentally estranged from the high-integrity worldbuilding of a Tolkien, but it’s done pretty well here. The tone is good: A novel ecology that has obviously not received any real thought, a talking dog, T&A outfits, a chibikko miko mecha pilot who parks her machine in a massive chipped-stone dungeon cleverly “hidden” under a retracting pool in a ruined city. It’s the right level of absurdity to sustain the premise, and the Shirō Sagisu music is nice as usual.
Thankfully, the end result is the right one: The virginal protagonist does indeed hit on the guy she likes, despite the evil wizard of the metaphor world clearly being a symbol of him, to the point of taking his place in the climactic struggle.
References here: “Munto” (2003).