(CNN) -- Early in Michael Mann's vivid, incisive, but half-cocked gangster opus "Public Enemies," Johnny Depp's John Dillinger returns to jail a few scant months after leaving it.



Johnny Depp plays the charismatic John Dillinger in "Public Enemies."



Only this time he's just visiting -- and he's taking his friends out with him.



It's an audacious opening gambit, and when the getaway gets messy -- one of the gang panics and soon bullets are flying all over the place -- we glimpse another insight into what makes Dillinger tick. As he clings to a wounded comrade for dear life, and stares death long in the face, he has to make a decision: What to do with the guy who panicked and brought this upon them?



Dillinger lets him go.



Based on Bryan Burrough's well-sourced account of the Depression-era crime wave that gave rise not only to Dillinger, but also to a whole gallery of criminal poster boys -- Machine Gun Kelly, Pretty Boy Floyd, Baby Face Nelson, the Barker gang, Bonnie and Clyde -- "Public Enemies" whittles the book down to its most dramatic duel: the nationwide manhunt for Dillinger presided over by J. Edgar Hoover (a knockout Billy Crudup) and led by his Chicago, Illinois, bureau chief, Melvin Purvis (Christian Bale).



Dillinger and Purvis assumed folk-hero proportions in their day. According to Burrough, when newsreels showed Dillinger -- public enemy No. 1 -- he was applauded more loudly than the president.



A 20th-century Jesse James, he was an underdog with a reputation for fairness. It was said he never killed anybody, and he was gallant and jocular with members of the public, once offering his overcoat to a kidnapped bank teller he had taken as a human shield.



The role is tailor-made for a self-styled rebel like Depp. He understands the outlaw's swagger, the ferocity that sits hand in glove with his soft-spoken sensitivity.



All the romance in the picture comes from Depp: the graceful ease with which he vaults a bank railing, his astonishing self-confidence and his dedicated courtship of hat-check girl Billie Frechette (an eager Marion Cotillard). She's swept up less by the high life he promises than the passionate conviction of his pitch.



Burrough paints Purvis as an ineffectual, even inept agent who was fortunate to be in the right place at the right time to nab Floyd, Nelson and Dillinger. The movie has no truck with such revisionism, but betrays little interest in Bale's dour, narrow lawman.



The film's parallel cop-and-robber structure recalls Mann's modern classic, "Heat." Purvis and Dillinger meet only once -- to talk -- and then face off just once more, at the climax, to kill and be killed. If the confrontation of Bale and Depp doesn't pack the same iconic punch as "Heat's" Al Pacino and Robert De Niro, the (entirely fictitious) exchange in a Midwestern jail cell remains central to the film.



At one point, Dillinger reprimands Purvis for shooting down Pretty Boy Floyd, extending the poetic license still further -- as a point of historical fact Floyd died several months after Dillinger, and though Purvis was at the scene he almost certainly didn't pull the trigger. But Purvis did coordinate the execution of John Dillinger, an assassination as much as it was an attempted arrest, and maybe the nastiest crime in the picture. So when the incarcerated Depp advises the smug Bale that he should find a different line of work for his own peace of mind, his words carry a certain weight.



Still, the movie's resolve to take Dillinger at face value feels a bit perfunctory, even old hat. At 140 minutes it takes a long time to find its rhythm; indeed, this is one film that would be better if it were 20 minutes longer.



Still, there's little here that Arthur Penn didn't anticipate 40 years ago in "Bonnie and Clyde," except maybe the intriguing idea that organized crime pulled the
Depp plays who? Who does the film star? Who stars as bank robber John Dillinger? Whose Depp's costar? What is a solid gangster flick?
John Dillinger Johnny Depp Johnny (Christian Bale). "Public Enemies,"
question: Depp plays who?, answer: John Dillinger | question: Who does the film star?, answer: Johnny Depp | question: Who stars as bank robber John Dillinger?, answer: Johnny | question: Whose Depp's costar?, answer: (Christian Bale). | question: What is a solid gangster flick?, answer: "Public Enemies,"