While Black Mirror started out as a series exploring the myriad terrifying ways technology could impact our lives, it has since grown into a more general genre anthology. It’s nice when episodes have that techno focus, but it’s no longer a necessity. Case in point: “Demon 79,” a season 6 story that’s pure classic horror homage. Its premise wouldn’t be out of place in a collection like Tales From the Crypt or Cabinet of Curiosities. But don’t let the lack of Black Mirror-ness dissuade you — this episode is a blast of Hitchcockian scares with ...