Yakuza is alot of things. the story usually involve some kind of crime drama/conspiracy that is well executed, well written and with cutscenes that are well directed and voiced that involve alot of things. it is also over the top, but not in uber ridiculous way. some way it's kinda like 80's martial arts action movies. most character are likeable and well written. there is combat that is also well done. most of the games have different "styles" of combat that you can develop trough skill tree to earn more combos, and you can look so fucking cool pulling off combos and beating thugs under your heel.
under the outer layer, there is also this wacky aspect to yakuza. the side missions usually involve mini-story, sometimes hilarious, sometimes wholesome and heartwarming, sometimes both and they usually are also filled with endearing minor characters. it plays alot with tone and pulled it off. it's sometimes wacky, serious, cool, weird but nothing feel out of place or forced. you usually encounter these side stories exploring your map.
on the outermost layer there is the minigame aspect to the game, and it's full of optional side activities that are usually well done and sometimes rewarding, but i don't really care about the scores of these minigames, but stuff like bowling, karaoke, etc are fun and shogi is always great to play.
the map. oh the map is one of my favorite part of the series. sure, they reuse asset but kamurocho is one of my favorite place in videogame ever. it may seem "cramped" but the density, detail, atmosphere is amazing. the fact that it's city block world, it lets you really become familiar and love that place as much as your home. turn off the minimap, explore the areas, nook and crannys by yakuza kiwami 2, i know the layout like my own neighborhood. where my favorite restaurants, sellers, etc.
the game have weaknesses like some substories force you to play minigames you might not like, or some of the world encounter can be annoying, but the series overall is super fun.
alot of people love it for different reason. it might be fun for some messing around in the world, grinding kiryu to some battle beast of a fighter, participating in challenges. i myself really like the story , the little story and worldbuilding in the sidequests, and the overall atmosphere of the city that is nearly unmatched. the combat is very good too and pretty deep especially in harder difficulty where you really have to consider combos and items.
to SCS)
