Carrie (1976)

Carrie has her period in the shower, she has an abusive religious lunatic for a mom ("They're all gonna laugh at you!"—right?), she has pig blood dumped on her at the prom, she telekinetically kills everyone, including her mom, with flying knives, and then she grabs some girl's ankle from her grave. But that last part's a dream. OR IS IT?

[NOTES: (1) It may be that I've actually successfully summarized the entire plot of the movie: this is another one that I can't see as being much longer than 20 minutes long. (2) When I saw the Sex and the City 2 teaser poster, I honestly thought that it was for a Carrie sequel, but of course it wasn't. OR WAS IT?]

But, you know, in the end it's a pretty happy story.