A girl is told a fantasy story ... who cares?

First I have to ask, did you actually watch the film? If so, it appears you missed the point of the plot.

Alexandria is a Romanian immigrant child, who witnessed her father being murdered and village burned down, before her mother brought she and her siblings to California to work as migrant workers. You'd agree that would be traumatic, I assume?

She, like Roy, had a fall; she broke her arm, he fared far worse. She's lonely; her mother and siblings can only get away infrequently to visit her. He's lonely and broken. They form a bond, a friendship. Roy becomes a father figure to her, and tries to use her to get drugs so he can kill himself, by enticing her with the story.

The more despondent he becomes, the more violent and hopeless the story becomes. Alexandria sees where the story is going, and subconsciously knows it's attached to Roy and his future (or lack of one). She doesn't want to lose her friend, and father surrogate, having already witnessed her father's murder. I'd say the stakes were high for both of them.

^That

A bit harsh, but basically a lot like how I feel about this movie.
I like that is is bizar and very visual.
But the pacing is awfully slow.
The filmers and editors are trying too hard to show off how awesome they are in shooting scenes so the need to be in abundance and in slow motion.
There are to much scenes with the girl just doing boring kids stuff like we must go "aaaww" over pretty much every movement that a kid makes.
And the story is just an over the top story made up on the fly with clear includement of stuff and people they just recenly saw or talked about.
I guess that is supposed to be deep. It is very very deep when you are shallow.

To me, this movie is a naked emperor.