Essential elements of a noir tribute crime flick: Lantern jaws under snap brim hats. Redheads bursting out of sheath dresses. And tommy guns blazing crazily. (Let's ignore that firearms debate for 30 seconds.) All are present and correct in the blistering trailer for Gangster Squad, along with rap music (blame Baz Luhrmann) and also Sean Penn, apparently sporting the same prosthetic William Forsythe used in that Warren Beatty Dick Tracy movie.