Most fairy tales were told and retold countless times before Walt Disney ever got his hands on them, and yet, the sensibility behind such animated classics as “Snow White and the Seven Dwarfs” and “Sleeping Beauty” has proven so popular on such an international scale that few know these stories’ darker origins. The family-friendly studio’s more-wholesome-than-horrifying approach gives Norwegian writer-director Emilie Blichfeldt plenty of room to push back with “The Ugly Stepsister,” a deliciously extreme take on the beloved “Cinderella” legend, complete with broken noses, severed toes and other gory details befitting the Grimm bros.

Premiering in the Midnight section of the Sundance Film Festival, the graphic update swipes a different page from the Disney playbook: Instead of focusing on the familiar wench-in-waiting, Blichfeldt recenters her version on one of the tale’s iconic antagonists, finding empathy for the pig-nosed, slightly plump stepsister (played by Lea Myren) who’s...