Leave the World Behind,” writer/director and “Mr. Robot” creator Sam Esmail’s suspenseful, psychological thriller, understands the general mechanics of the post-apocalyptic genre. There is the pretentious family caught in world-altering circumstances. “I f*cking hate people,” says Amanda Sandford (Julia Roberts), as she stares jadedly from the window of her luxe Brooklyn apartment. And so Amanda and her amiable husband Clay (Ethan Hawke) take their children Rose (Farrah Mackenzie) and Archie (Charlie Evans) to a lavish Long Island mansion for the weekend. Similar to other disaster flicks, this film worms through oddball characters, takes interest in the disintegration of society, and the tension that arises from disparate people pushed to survive with each other. But “Leave the World Behind” struggles where it matters most, fashioning real stakes to accompany the turmoil.