Three-and-a-half stars. R. 105 minutes. From its very first moments, “Get Out” puts viewers in a squirminducing state of discomfort and outright hilarity that doesn’t let up until its go-for-broke final act. The sly, sure-footed directorial debut of Jordan Peele — one half of the brilliant comic duo Key and Peele — this horror film has roots as firmly planted in the works of Jonathan Swift as John Carpenter, interleaving acidic social satire between the jump scares. As deeply serious as it is deeply funny, “Get Out” is perfectly timed to jolt audiences out of their midwinter blahs, delivering classic genre whammies with a generous serving of cultural critique. That opening scene, by the way, takes place on a leafy residential street at night, when an African-American man is chatting on his phone, trying to find an address.