Well it all depends on if you are familiar with the DW series or if you are a fan of HnK. Im not too familiar with DW, but I am afan of HnK, so the game, while not perfect, is still pretty good IMO.
Its seems one of it's problems is the story. It is, basically, like one review put it, "Fist of the North Star Cliff's notes". It covers the really important parts of the story up to the final fight with Raoh, but tends to skip some details. (which technically, are important in their own right) Such as, and this is the biggest one- Finishers. When you finish the boss, they characters dont always use the finisher they originally used in the story. But aside from that, the story is told alright. In fact, some parts are not shown because they correspond to another character's story line. So basically, only by playing all the characters do you get the full story.
Another issue is that boss fights can be VERY cheap at times.
Oh, another complaint is that the localized versions had the theme song from the credits removed.
Hokuto Musou Official Theme Song With Lyric (http://www.youtube.com/watch?v=26ek0CKwItk#)
But my griping aside, I still think it's a fun game. Addictive too. If anything, it expects you to already know the story. Its catered to the fans of the series.