As someone who, at best, only had a passing interest in the yakuza series, this is some GOTY material right here....and im only on chapter 5 and i've probably dumped in like 20+ hrs already and can't wait to dump in 20 more.
Everything gels together in a way that I would have never imagined. On paper you have so many elements in this game, from it's serious story, heart warming side missions and unapologetic pervertedness, that have no business being as cohesive as they are.
The characters are fantastic. To watch them navigate their individual plights but still maintain a sense of honor and respect for their japanese/yakuza culture that otherwise constantly hands them a pile of shit is pretty amazing. Using Kiryu as a quick example, if this game were set in America, once he's excommunicated from the Yakuza, it would basically just be a renegade revenge fueled bloodbath to single-handedly take down everyone in the yakuza and anyone who stands in his way by any means necessary; It'd basically be mafia 3. However, in yakuza 0, Kiryou (at this point in the story) only has an issue with Kuze and still holds the yakuza and the dojima family in high respect. Hell, Kiryu does everything to avoid fights both in the main story and in the side missions until he's given no choice.
And it's this level of honor and respect that punctuates the fantastic humor in this game. The protags are so straightfaced and dead pan most of the time that often they're not in on the joke until its over and the times where they are in on it, its just enough outside of their character that it presents this humorous level of awkwardness without feeling cringy.
Even the stuff that's obscenely perverted (and there's a good amount of it!) comes off far more over the top and comical than offensive. How the hell they managed to pull that off is impressive in it's own right.
The side missions have all been really good and have heart and charm, 2nd only the witcher 3. My only issue is that all the side missions end up on a very positive note. It'd be interesting to have some of the side missions turn out "bad" even with your best intentions on trying to help the situation.
And the wealth of content here is absolutely ASTOUNDING. The side missions, the mini games, building a business empire....there's just no shortage of things to do. All the more impressive is the fact that everything serves a purpose beyond just being there for show. All the mini games contribute to getting you CP points. Building your empire brings in copious amounts of money that helps with upgrading your abilities. Doing side missions will reward you with on the spot rewards and in some cases people will ultimately offer their services to aide you in your business as a token of their appreciation. There's a lot of time wasters in the game yet you're never actually wasting your time.
All in all, the game is just phenomenal and i cant wait to see it through for everything that it's worth. I am now definitely a fan of the series.