The title (possible spoilers)
What do you make of the title of the film? Michaek Atkinson explains in his essay, Vengeance Is Mine: Civilization and Its Discontents (on the Criterion Collection's website) that it's inspired from the Bible (Romans 12:19):
Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, "Vengeance is mine, I will repay, says the Lord."
Does the film suggest that all people eventually pay for their own sins and crimes? The story's infested with sleazy characters and most of them end up killed.