The new horror movie lets audiences yell at the protagonist’s baffling behavior for most of the movie, before revealing why it all makes sense. Photo: A24 Spoilers follow for the plot and ending of Backrooms . The cultural shift that turned horror cinema from a disreputable, rarely respected grind-house film genre into a billion-dollar-a-year mainstream business has done wonders for the genre’s overall quality. American horror movies from the ’60s to the ’80s in particular tended to suffer from