not sure if I want to make a pun about the band, Chicago, the song, The Night Chicago Died, or Bruce Willis... 455

You got a deathwish or something? :))

The original, with Charles Bronson, must have been hugely satisfying for sociopathic viewers. That's what's scary about the film. It's propaganda for unregulated private gun ownership and a call to vigilante justice. Even the cops seem to see it that way; Bronson becomes a folk hero as the New York Vigilante, and the mugging rate drops fifty percent. So the police want to catch Bronson, not to prosecute him for murder, but to offer him a deal: Get out of town, stay out of town, and we'll forget this. Bronson accepts the deal, and in the movie's last scene we see him taking an imaginary bead on a couple of goons in Chicago.
Nothing stands between the innocent and the blood-lusting vigilante but the Rule of Law. A good example is The Ox-Bow Incident (1944) with Dana Andrews, Henry Fonda, Anthony Quinn, et al.