I've always been kind of partial to Michael Mann's crime stories. Consider some of these titles: "Miami Vice," "The Insider," "Collateral," and upcoming John Dillinger movie "Public Enemies." He certainly tells a good cop and robber story where both the traditional good guy and bad guy characters are presented as being ethically compromised. "Heat" was the movie that really launched his career and that concept is definitely at play here.
One of the most exciting aspects of "Heat" was that for the first time ever, Robert De Niro and Al Pacino would be sharing the screen in the same movie. Granted, De Niro and Al Pacino were both in Godfather II, but because of the different stories being told set in different times they never were on screen at the same time. Also, don't make the common mistake of thinking that they were both in "Goodfellas," because that of course, is Joe Pesci, not Al Pacino that plays the loose cannon sidekick. So for the first time sharing a screen together are two Hollywood megastars made famous for their roles as gangsters. Take a look at the poster, you know there's going to be some high pressure acting going on between them right?:
Well... un pocito. Since Al Pacino plays a cop and Robert De Niro plays a bank robber, they only cross paths in two scenes. Even more frustrating for the viewer who is consciously aware of how exciting it is to have these two in the same movie, the director seems to have made a concerted effort to not have both of their faces in the same shot at any point during the movie. This leads to a disproportionate use of over the shoulder shots during the few scenes that their characters share. The scene in a diner is pretty cool though.
Val Kilmer plays De Niro's sidekick, a character named Chris Shiherlis. He's a family man with an unseemly long blond ponytail. He's also got some intense gambling debts which kind of force his hand into taking part in some increasingly brazen bank robberies even though the wifey is clearly sick of this life and trying to leave him. Even though he's one of four characters in the sort of inner circle of criminals, you can easily tell the De Niro likes him better than Tom Sizemore or that terrifying Mexican guy (whose so scary that the character is named after the actor!).