Story for first game goes like this, you take the blame for killing someone, go to jail for a decade, everyone triess to kill you cause they think you murdered that person, you find a girl looking for her mother, you help her out and story escalates further. There are a lot of plot twists in this game, but are for the better, plot unfolds itself in a proper manner through cutscenes, you get attached to the characters.
Second game takes place a year after the first, character comes back to prevent an all out war from happening. You get to know more about characters from the 1st game and meet new ones.
Gameplay primarily consists of random street brawls, mainly hand combat, you can use weapons and items you find, use the enviroment, and can also do tag team moves. There are times where you have to go to meet people at certain places. You can do side quests that get unlocked as you progress through the game. You can play mini-games like arcade games, baseball, mahjong etc. You can play as a host or run your own host bar.
Each game will take about 20 hours to complete for the main story, more if you do side quests. You can also unlock boss battles, replay with upgrades and money.
Its like Shenmue but with more action, swears and more intended for a mature audience. If the gameplay doesn't work well for you, the story will.