It was amazing. It's about a group of childhood friends who grew apart as they grew up, and the one who got teased/picked on in the past is now basically a jerk. He is ruining the city and building casinos, killing people who owe him money for land, etc. It's a really fast paced movie with lots of fighting and (surprise) violence, and the break dance martial arts scene in the Korean city streets was my favorite part of the entire movie. I suspect this might be the case for other viewers, too. The woman sitting next to me was the type who got so shocked by violence and bloodiness that she would nervously laugh the whole time. That was a little annoying, but the movie was excellent enough to distract me.
Unfortunately, City of Violence isn't playing at NYAFF anymore, but you can probably rent it on Netflix or buy it here.