I cannot stress enough the difference between jdrama and kdrama.
When it comes to topic, jdrama has no taboo and is prepared to talk about anything and everything. Although some stuff are not allowed to be seen on screen, you get enough of hinted material to visualize yourself.
Kdrama on the other hand stays shy of disturbing topics or threads very carefully and leaves the actual spectacle for their movies. There are a few episodic products that are different from the general offer, but these are superrare and are made specifically for international audience (Netflix, YT). Most of the rest are romances, comedies and crime dramas that don't venture much into filth.
Because I've mentioned movies, it's a competition who'll show more sick stuff between the two countries.
It's no secret that korean thrillers are probably the best worldwide thrillers pastHitchcock, seems that they all study suspense and twists in Korea and my god you can see some seriously disturbing stuff in those - which is positive in my book.
On the other hand, Japan has Takashi Miike and Sion Sono, two totally crazy filmmakers capable of such unique stuff no other country can even imagine of making.
Back to videogames - how many singleplayer RPGs Korea has? So far I saw - only one.
I have no idea what's lackluster in Yakuza6 but it's instabuy for me.