In the shadow of the South Korean movie hype that brought masters like Bong Joon Ho into the international limelight there was also a small but unique movement to emancipate the country as a quality provider of animated features in its own right, and not just a cheap location for Japan and the US to outsource their inbetweening to. Echoing the same development rival Japan went through when it emerged in the eighties as an animation powerhouse. Unfortunately, close to 15 years later now, 2D animation hasn't taken off to the same degree in South Korea despite the undeniable qualities of movies like Yobi the five tailed fox, wonderful days or this vulgar gem whose title I literally can't translate into English because it would violate imdb language standards.
Aachi & Ssipak is a satirical view of modern mass media with a few subtle stabs at North Korea and many not so subtle references to classic movies, spiced up with a very dark and crass sense of humour.
In the future the only remaining energy source is fecal matter, hence feces become quasi-religious symbols. Citizens get rewarded for their business with lollipop-like drugs that eventually turn them into tiny smurf-esque creatures called the diaper gang that can only live on these drugs and thus roam the cities and desolate wastelands as marauding scavengers.
...It all makes a little more sense in the context of the movie...
Despite the cartoonish look this isn't a movie for children (unless you're a really cool parent). It's filled with sexuality, graphic violence and vulgar slang (especially in the original Korean dub). Yet it never feels like it's trying to be edgy, it just has this natural offbeat punkrock FU attitude that you will either love or hate. I find it intensely likeable myself.
Give it a chance and you'll be rewarded with something very unique and unironically some of the best animated action scenes in recent memory.