Writer-director Jorge Michel Grau faces a steep challenge with We Are What We Are. As the maker of an existential drama centered on a morose family of Mexican cannibals, Grau must find some way to connect his audience to the material, to unearth the humanity behind a gruesome, depressing subject. Let the Right One In and Let Me In, its American remake, established a template for this sort of enterprise, mixing the pangs of young love and the aching loneliness of the vampire’s everyday existence with the characteristic gore of a genre flick. Yet, cannibals are less sympathetic than vampires, the pop culture ghouls-of-the-moment, whose survival depends on human blood. There’s something far less romantic about humans who devour other humans just because they’ve developed a taste for them instead of, oh, McDonald’s. Filmmakers have traditionally understood this: Aside from one Hannibal Lecter, it’d be hard to finger a movie cannibal of note.