Hell, I disliked this enough that I'm just going full spoiler. About the only way it is interesting is in seeing the dichotomy of largely liberal Hollywood producing gun violence. So to justify Bale murdering the bad guy, modern Hollywood has to load the deck so thoroughly that:
Bale is caring for a bed-ridden father.
Bale spends every waking hour earning money to bail out his brother.
Bale goes to prison for an almost entirely accidental crime.
While in prison the love of his life leaves him.
After getting out of prison, he begins restoring his house in his shattered neighborhood.
His brother gets killed even after following the bad guy's wishes, despite getting the crap kicked out of him for doing so.
The bad guy is, of course, a drug kingpin and untouchable by law enforcement. He is also a drug addict himself, for no reason other than to stack the deck more against him.
Bale's plot to kill the bad guy still results in the death of the closest thing to a friend Bale has in the movie (it seriously could have used more than 12 or so speaking parts).
And yet I'm still wondering why the movie doesn't end with Bale in prison - he kills the bad guy in full view of the local sheriff. It heavily smells like that was the original ending, until focus testers threw crap at the screen.
Seriously, unless you are a film school student working on a thesis on "feel bad 'action' movies*", stay away.
*Oddly, the champ of the genre, Blood Diamond, starred Leo DiCaprio, one of the 97 producers on this.