Just a quick note on an “Honorable Mention” – the movie Nightbreed based on a Clive Barker story. This is an example of “If the story were about her” – the protagonist’s girlfriend Lori goes in search of answers about her supposedly-dead boyfriend, and ends up discovering the strange world of Midian. She saves a child and is subsequently allowed into the otherworld, goes literally underground, and eventually unites with the so-called monsters there against an evil police captain and psychiatrist. Since it’s not her story, she doesn’t get the final confrontation and certain other necessary GU elements, but from her perspective, it comes close to qualifying.
(Edited to add: Having recently viewed the newly released Director’s Cut of this movie, I noticed that Lori is given more background and screen time in this version, and it makes the whole thing a bit more of an authentic GU story.)