I think it is a pretty good movie...! Well, first of all, I have to make it clear that I am not an American so that by no means shall I know this character better than any American. Moreover, I believe a foreigner can be more easily attracted by this film, since he/she doesn't know it equally well as an American. And, my comments are based on the above statement and a possibly consequentially biased perspective.
I believe all shall agree that the casting is wonderful. Johnny Depp is the one that brings John Dillinger back to life. I was told that the director Michael Mann initially wanted Leonardo DiCaprio. Though I agree that Leonardo is also a good actor, I still believe that Johnny Depp is THE ONE. His wild and sexy charms, especially that kind of tricky smiles that hold a natural contempt against authorities, is just what we can see from a poster of John Dillinger.
As I watched the film, I gradually got convinced of this. Johnny has shown his understanding of the character and put on his face very naturally the multidimensional inner world of Dillinger: On the one hand, Dillinger holds unmatchable confidence in his strong executive abilities in cold blood, a defiance against then police officials, and quite a sense of narcissism oriented towards public popularity. On the other, he was a dreamer, lover and believer in freedom. Johnny Depp, with his complicated temperament and unbelievable range of roles, has nailed everything of the above.
Christian Bale also did a good job. I cannot understand those who claimed he was too obscure in the film. Let's judge his performance based on the character. Purvis didn't boast an out-going personality at all. Reviewing the history, we can find he was just the type of person who believed in the public good, the ultimate right, and gave his best to his job. That is why Christian Bale's controlled performance delivered a decent result, let us say "Grace Under Pressure". But in the Little Bohemian Lodge gun fights, Christian Bale kept shooting the gang nearly dead, with hatred glaring...This was an burst-out and a release of long-time pressure and hatred.
Another issue is HD cinematography. Since the director favored long scenes of gunfighting. He'd better do it by HD. Besides, the great sense of style of 30s America also needs HD to make the best of it. Still, there were so many night scenes, and the actors' movements and facial expressions need to be made clean, so HD is needed. We have to admit that HD was used because the director needed it...
Some viewers argued that there is a sort of inconsistency in cinematography of the film. Sometimes it looked like a master's work, and sometimes a beginner's. I guess they argued this because some scenes did look dodgy, unstable, and almost impatient, especially those gunfights. But I think there was a purpose behind it: the director wanted to make the gunfight scenes real, something you are supposed to see when you are shooting the gangs while chasing them...Yet, we have to admit that the result, when seen from the whole movie, is not so good, largely because you cannot only make the gunfights something like a documentary and at the same time the rest scenes a drama...
Though I love its casting, its cinematography, its fashion style, and its score, I have to say the plot is a failure, and I am pretty sure that this failure will much likely lead to the failure of the movie as a whole.
Just like what I stated in the beginning of this article, many Americans knew the episode pretty well. But this movie certainly didn't make them know it better. The plot can be easily summarized as "Dillinger escaped - He robbed again - In jail but escaped again - robbed and robbed - finally got caught and dead"...I can see the movie's writers studied Dillinger's life and intended to attach importance to the most decisive moments, but we all knew them, didn't we? Even a foreigner like me can know all these from Wikipedia, let alone the Americans who worshiped him for decades...
But it will be unfair if we say the director made no effort to explore more of the character. Echoing what I said about Johhny Depp's great performance, I believe the director tried to show how complicated John Dillinger was as a person. But, he only did it by arranging several dialogs with Marion Coutillard, Christian Bale, and the gang friends...and these were just NOT ENOUGH. Besides, these dialogs, though pretty brilliantly written, were too subtle in their expression and not likely to be spoken by a man who robbed and killed. More clever plots that told his deep inside shall be added, and the gunfight scenes deserved to be cut...
As a summary, I would say this is a good film, made by supreme technical skills and a carefully-chosen casting. The fashion style, the sound mixing, the score and the controversial HD cinematography were to me fantastic, but the plot was not good, which would ultimately gave it a mediocre reception from the critics...