You may know of J. Robert Oppenheimer as the father of the atomic bomb. But that's only one part of the theoretical physicist's story, told in an epic way in Christopher Nolan's Oppenheimer, out Friday. Based on Kai Bird and Martin J. Sherman's 2005 biography American Prometheus and starring Cillian Murphy, Emily Blunt, Matt Damon, Robert Downey Jr., and Florence Pugh, the film has a 94% rating from critics on Rotten Tomatoes. Here's what they're saying: