Absolutely, the DVD's for it kinda suck though (the picture is too dark -- though it certainly fits the mood). The only yakuza film I'd avoid is BRother, which a lot of people love, but I don't... well.. it's like an American remake of Sonatine, but halfway through, you can tell Kitano got pissed off, and the film becomes kinda like a frustrating, awkward parody of American films after a certain point. It is his most violent, and it's downright bizarre at times... but I can't really take it seriously as a movie. And I've tried.
VIOLENT COP is his darkest film -- in fact, it's one of the darkest films ever. It's up there (down there?) with Bad Lieutenant.
I really like Boiling Point but it took a few watches for me to get into it -- there's no music in it whatsoever. Very strange. Watch this trailer:
http://www.youtube.com/watch?v=sMow8XsAVt4
I'd reccomend Dolls, Kikajiro, and Achilles & the Tortoise to you after that; they're not really violent but they're just as depressive, deadpan, and dark... DOLLS is very very cynical but absolute beautiful... Achilles and the Tortoise is simply one of the darkest films ever, though it doesn't seem like it because of all the beautiful art and whatnot... Kikajiro makes me cry. It's hilarious but very very sad. I love all his films like I said. You'll either get hooked like I did or you won't. He's got a very particular style. But Scene at the Sea is just so overwhelmingly beautiful too. i DUNNO. Just amazing director.