This is a crude, brutal, harsh look at the reality of bullying and what could happen when kids are brought to the brink of their capacity to handle things on their own. And everything gets magnified by a society where social classes tend to protect the wealthy and automatically turn a blind eye to the unprotected.
The story starts on the present with a look at the current state of the lives of the protagonists and then falls back to a crucial point in their lives which end up defining them. The story progresses rapidly as the conflict escalates between the kids and there is a sense of realism that I haven't experience since I last watched The Grave of the Fireflies and Barefoot Gen. If you have watched any of those then you'll know what I mean by "realism" and what kind of story to expect from this movie. This realism is in part due to the fact that is based on a true story.
A lot of anger is portrayed here, there are a lot of brutal scenes involving kids fighting, physical abuse. animal abuse, discrimination, loathing, etc, etc., but perhaps what makes it more terrifying is the psychological abuse and the state of mind these kids are in, feeling trapped and desperate by their lives. Enough said that this is not a story that anyone can watch nor appreciate its message.
"Pain is represented as something very real, enough to make one wince. ... The King of Pigs captures many subtle class gradations in Korean society and shows how it corrupts human interaction." -Maggie Lee of The Hollywood Reporter
The animation is very different from the typical Japanese style and works well matching the feeling of the story with a grotesque look of the characters.
Regarding sound, there is a lot of silence on several scenes that convey the feeling of desolation and alienation.
The characters are well written and easy to relate if you have the unfortunate situation of having met people like the dogs or pigs to some degree, hopefully not to this degree, lol. You'll get to see the story through their eyes and the type of society that in part, is to blame for the outcome of the story.
Overall, if you are into romance and like to watch cute things stay as far away from this movie and never look back. If on the other hand, you don't mind to peek into the dark side or try to understand why people do awful things to each other, and how some environments can push people to the brink, then you'll find this movie to be a hidden gem!