I think Michael Mann is a good director, I hated Miami Vice, but I loved the way it was shot, and Mann sticks to that gritty, harsh lighting and natural set-up in this film. Mann really comes into his own when it comes to shoot-outs. He just has a way of shooting gunfire that is unmatched by anyone else. The sound isn't cartoony and I love knowing that he's not talking down to me and trying to make a gunfight pretty. Bullets tear into and destroy everything in their path and I love it.
Johnny Depp really made this movie for me, and even though there was a rather impressive supporting cast I really didn't care about them that much. He makes the most of all his screen time and appropriates Dillinger's much revered nonchalant attitude with ease. While not being emotional, you can see that losing men and having the net tighten around his wily band weighs heavily on him, and every loss is a personal failure on his part.
I loved that the love story wasn't really a love story. Dillinger merely wants to protect something that can't protect itself and Billie just needs someone to take care of her. It's not so much love as it is a necessity in order to feel complete.
The film is confident in its delivery of the last 18 months of Dillinger's life, I felt like when I watched it it was less a movie than it was a cross section of how it all went down. It doesn't pander to the audience or explain how the characters got to where they are, and I love that. We all know how the story ends, and the movie doesn't serve to explain WHY what happens happens, but rather THAT what happens happens.
I'm sure this is one of those love-it-or-hate-it movies for most people, but I think I just appreciated it for the fact that it didn't SAY anything, it just puts together a series of images based on the researched history of one man's life and provides us with images of how it may have happened. It's excellence as a film is completely dependent upon its simplicity, and because of that it succeeds.