Even though Onimusha 2 is not getting the best of reviews, do not even bother to beleive them, that is, if you liked the first game at all.
Onimusha 2 is an upgrade on everything from the first Onimusha, including the voice acting, the graphics, and the game play. The game keeps such things in it as taking in the souls, and it is cleverly different from how Onimusha did it.
Playing through the game, you realize you recognize some parts from Onimusha. This game has a great tie in to its original. The fighting is just as good as the first game, and the new features where you have a teammate help you fight is awesome, especially when you are fighting one of the tough bad guys.
Overall I think this game surpasses the first by far, and could be the best PS2 game released this year to date.