What do Gen Zers do during a hurricane? Correct, they party with zucchini bread and a version of the game “Werewolf” called “Bodies Bodies Bodies,” which soon shifts gears into reality as the first body appears. Dutch actor and director Halina Reijn serves a cheerful, clever whodunit in hyperpop mode (there will be glowsticks!) that also works as a satirical portrait of a generation whose well-groomed social-media identities escalate or collapse as soon as the power goes out, taking the internet with it.