A triumph of production design but a pretty dull kill-’em-up, this 1940s-set L.A. cops vs. gangsters movie falls short. Directed by Ruben Fleischer (Zombieland) and based on a nonfiction book, the movie’s violence is over the top and its script is underwhelming. Sgt. O’Mara (Josh Brolin) and his team of rogue officers (Ryan Gosling, Giovanni Ribisi, etc.) take on the notorious Mickey Cohen, played with relish by Sean Penn. A couple of fine performances play off the iconic set design and help along the revenge killings. It’s entertaining enough, but as a whole it lacks a lot.