I always say that no one does dark and twisted stories like Japan do. Smoking is exactly like that, gruesome, brutal and disgusting that it's sometimes even hard to watch, but it also had a main storyline written around really likeable and well-written characters which makes the entire experience really unique because of the emotional investment you had to endure. Even if you are hesistant to accept the character's actions at first you'll end up rooting for them as soon as you realize they're another victims of a vicious circle of crime. There is no good in this story but there is definitely a lot of evil.
There is also that perverse satisfaction of watching and accepting lynch as a right form of seeking justice on murderers, rapists and members of the mafia. The fact that all of this happens in a criminal 'demimonde' is almost like a permission to accept that unlawful method thus our deepest desire to punish those monsters is alleviated.
Every piece of the story is well thought out and it comes together into enjoyable, thrilling and satisfactory ending. Definitely worth a watch especially if you're in the mood for something bold, ruthless, unusual and weirdly entertaining.