More of the same.
Samanasuke Akechi, the main character of the first game, is no longer in the lead. In fact, he's not even in this game. You'll be controlling Jubei Yagyu this time. In the beginning of the game, Jubei returns to his village to find it in ruins. When he finds out that Nobunaga is to blame, he sets out on a quest to find and kill this new King of Demons. The story this time is definitely told better, but it still takes backseat to the gameplay.
For reasons beyond my understanding, Capcom stubbornly refused to change the control scheme. Instead of making this game control like Devil May Cry, it controls like the original. This upset me very much. The game would be so much more fun and engaging if these controls were just better! The other gameplay elements are also very similar to the original. You collect the souls of demons as you kill them. Red souls allow you to upgrade your weapons and armor, blue souls replenish magic, and yellow souls replenish health. This time around you have four weapons instead of three (not counting the guns), and each weapon still has one magic attack. The puzzles this time are a bit tougher, and the enemies are smarter and stronger. All in all, it's a harder game, but also better. Enemies drop gold, which can be used to purchase gifts. You give these gifts to four different characters. If they like what you give them, the bond between you and that character grows. This determines which character joins you in battle and where the storyline will branch. It's an interesting concept, but the developer didn't flesh it out enough.
The graphics this time around are obviously a step-up from the original. The pre-rendered backgrounds are just as beautiful as before, the CG is even better, and character models and animations are slicker.
The game's soundtrack is great, with perfectly fitting tracks. However, in another poor decision, Capcom left out Japanese voice-overs in this game. This means you're stuck with the English, which is just as horrendous as in the original. The terrible voice work seriously detracts from the mood of the game.
The adventure is longer this time around, coming in at just under 10 hours. Still not much, but better than the original's four hours. Several minigames, unlockables, and different difficulty levels help lengthen the life of the game.
Onimusha 2: Samurai's Destiny is a good game, but if Capcom just looked into the many problems I mentioned, the game wouldn't feel like more of the same.