Any Yakuza fan is in for a real treat with this game. The majority of the mechanics that fans have come to love in the series are mostly intact, stuff like karaoke, playing arcade games at Club Sega, playing golf, pool, darts etc. so there's definitely no shortage of things to do.
Story pretty tongue-in-cheek but thoroughly entertaning from start to finish. Gameplay is very different from Yakuza games because you're mowing down thousands of zombies over the course of the main story in stead of fistfighting two or three thugs at once. There's still a lot of "faffing about" for anyone who like that sort of thing. there are tons of side quests and you can liberate stores from attacking zombies.
Dozens of hours of pure entertainment, and you could propably wring out closer to a hundred hours if you wanted to get the platinum trophy. Though I guess it's worth saying that if you don't like how the Yakuza mechanics feel, you may be put off by this game. The shooting mechanics feel vastly different to most western shooters.
This is already one of my absolute top games of 2012.