I'm a librarian who loves anime, manga, and reading a wide variety of genres.
The reason I remember the amusement park must be because it's awesome. They got attacked by the bloated headless corpse of another person who ended up in the Shadow World, they spotted some kind of weird blobby fetus creature off in the distance that I'm sure will cause them problems later on, and now they're walking around a mine ride that seems to be changing configuration when they're not looking.
They're definitely going to go into a house of mirrors at some point, I just know it.