Successfully complete the game with at least ten Fluorites found and save. Choose to start a new game and a "Shinnosuke Normal/Special" option will be available. The special version will show Shinnosuke in a panda costume with a baby panda in a front pocket clapping his hands. The panda suit will be shown in most short clips but not all FMV sequences.
Successfully complete the game with an "S" rank by getting most of the Fluorites. Choose to start a new game and an option for Kaede's new princess dragon design costume will be unlocked. She wears a red skirt with little wings on the back and a small tail.
Reach 20,000 souls and when you go to enhance you will have a better gauntlet. Go when you have 50 to get the Golden Ogre Gauntlet.
Capture 50,000 souls to get an even better gauntlet.
Bishamon O Flute
There are two places in there game where a very strange man hanging from the ceiling by his feet stares at you and ignores you. Later in the game, after you use the Evil Plate and open the door, he will talk to you. The man will now take you (whenever desired), to the Dark Realm. In the Dark Realm, kill monsters until two portals open; one to go up and one to go down. Keep going down to the last level (9th or 10th) while collecting all the items en route. Open the box on the deepest level to get the Bishamon O flute. Keep the flute just before the last fight with the Demon King. It is needed to get the Bishamon Sword.
In the Demon Realm (just after you destroy the Ultimate Creation) is a save mirror and three doors. Go to the door that resembles an iron gate. It will not open at first. Use the Bishimon O flute on it and enter. Go to the Bishimon Sword jutting out of the Skull Demon wall object and take it. It is more powerful than all three of your weapons put together, and it has speed. The sword also has an unlimited supply of magic.
When you have an Orb in your gauntlet, stand still for a few seconds and the eye will blink.
Use the following trick to save arrows/bullets and health when facing archers. To kill archers on roofs without being in their line of fire and using up your arrows or bullets, run directly under them where they cannot shoot you and use a Wind spell. It will reach high enough to destroy them in one blow. If another enemy is directly under the archer, you can use a Lightning spell on that target and it will kill the archer directly above him as well. You can now save all but two of your arrows and all of your bullets for the last three Bosses, where they are very useful.
Start off by doing any type of attack that will make Fortinbras fall to the ground (special attacks will make this quick and easy). From this point on, just keep kicking him to death. Press [Down] + [Attack], move forward, [Down] + [Attack], and repeat. This will take some time. You will never get hit, plus he will not be able to attack you if you can keep the chain kicks going.
Use this strategy if you have only your three normal weapons, and not the secret sword. Kick him, then slash him with the Enryuu Fire Sword. It is the strongest. Give him about five kicks and then deliver a Thunder Orb magic. Repeat this until you have no more Thunder magic remaining. Then, use the Wind Orb magic to knock him down. Use the Fire Orb and some kicks. Most of his attacks are easy to dodge, except the fire.
At the end of the game you should have all weapons and orbs at the maximum. When fighting Marcellus again, kick him and use the Thunder Orb's magic. For some reason, this is stronger than his other attacks.
Double Dark Realm rewards
If you are proficient in the Dark Realm, go through it twice, once from the Sentry Box room and once from the well in the west area. You will only get the Bishamon Ocarina and the Flourites the first time, but you can pick up Herbs, Medicines, and another Talisman on your second trip through.
Start a game and die about ten to fifteen times. After enough deaths, a message will appear, stating that a new easy mode is open. Note: You cannot achieve an S rank when playing in easy mode.
If you are low on health at the end of the game before facing the Boss go to the entrance of the keep for some battles. By now they should be easy -- just absorb the souls to raise your health.
When enhancing, collect about 25,000 souls. The number next to the soul meter should say 25. Enhance all of your weapons and Orbs to level two. After collecting the Wind Orb, use the remaining souls to bring that to level three, since it is weak.
Save your green and red mana for the fourth sword. It can be found just beyond the destroyed master's house (level four or five). By saving points, you can build the weapon up to full immediately.
Extra red souls
When fighting enemies around the floating blue skull-ball things, allow them to absorb the souls that are released when you slay an enemy. When you kill the skull-ball, you will get many more red souls than if you had absorbed them directly from the demon.
At the end of the game, when you are walking down the spiral pit, you will reach a pink and black blob that squirts out the "squid" monsters. Stand slightly to the left of where they land. When they are getting up (low enough that they are off-balance, but high enough that your foot can reach them), kick them over and stab them when they are laying down. You can easily get your red soul bar filled up 30 times using this technique.
Collect each of the following 20 Flourites to unlock the Oni Spirits mini-game.
A Flourite can be found in one of the small alcoves with brown doors near the Seiryu in the Under Temple area.
Just after the Boss fight in the South area, break some urns and search the floor under them to find a Flourite.
In the Keep after running into Kaede with Yumemaru, you will find the Flourite in a small cupboard over the treasure box near the stairs.
Go to the upstairs level of the Keep, and pass through the room just past the red magic door on the catwalk. Step through the next room to find the Flourite under the stairs, near the treasure box containing the Arrows.
Go to the upper reaches of the Keep. You will find a Flourite across from Volume Two of the Seiryu, just after the intermission sequence where Tokichiru takes off into the night.
Go to the Keep Underground. Head down the second hall of glass-encased red samurai. There is a Flourite in the left corner, near the last samurai.
Go to the Keep Underground. A Flourite is hidden inside the iron maiden in the same room where you get the Blue Key.
Go to the West Area when playing as Kaede. Find the secret room and use the Gear to enter. There is a Flourite in front of the Buddha statue.
Playing as Kaede in the West Area. Step into the burning room just past the gate that required the Gold and Silver Plates. Through the door left of this entrance is a narrow staircase. Next to the staircase in a heap of barrels, which contains a Flourite.
Go to the West area. You can find a Flourite just outside the door after obtaining the Vision Staff with Samanosuke.
Go to the West area. There is a Flourite on the hill with the sled just outside the castle.
Go to the West Area. This is a Flourite blinking in the path on your way to the room with the statue where you got the Matchlock.
Go to the East Area with Samanosuke. There is a bell on top the roof. There is a Flourite In the walkway around the bell.
Play as Samanosuke and find the Flourite on the pier just past the Magic Mirror room in the East Area.
Go to the East Area. Just when you begin playing as Kaede you will enter a shrine just past the locked door you need to pick. A Flourite can be found on the floor just to the right of the door.
When playing as Kaede in the East Area, climb a ladder in the bridge house Magic Mirror room. Destroy the crates here to find another Flourite.
Go to the East Area while playing as Kaede. You can find another Flourite on a chest in the room where you get the final book of the Suzaku.
A Flourite is in the sixth level of the Dark Realm.
A Flourite is in eleventh level of the Dark Realm.
A Flourite is in the seventeenth level of the Dark Realm.
There is a chest behind the waterfall containing the great armor.
Go to the room where you and Keade get trapped in and you have to pull the levers. Go through the levers. The chest that was in the corner behind the bars can now be reached. Inside the chest is the Holy Armor.
Just before fighting Fortinbras, when you are going down the spiral staircase, there are two Medicines. One is near a light about halfway down, and the other is near the blocked off area at the bottom. They are difficult to see.
Onimusha 2 FMV sequence
Successfully complete the game and save. Choose to start a new game and a "Special Report" option will be available. This allows a small sequence from the game's sequel to be viewed.
Speed trial mini-game
Collect all 20 Fluorites (blue rocks) during game play. Complete and save the game. The Onimusha Spirits speed trial mini-game will be unlocked. Successfully complete the mini-game to unlock an option to play the regular game with the Bishamon Sword, unlimited ammunition, 99 Soul Absorbers, and automatic magic regeneration.
Trapped floor sequence
When you get into the part where you have to go through traps, you will get to a trapped floor section. When you get here, you will see trapped floor parts marked with "X"s and "T"s. They are set in a random pattern each time. While walking across, you will notice that each different trap square makes other normal or trap squares fall in a certain direction (diagonally, up, down, left, or right). Also notice that they are always in an order to where you can get through. If you do not like the selection as it currently appears, exit the room and go back in to change it. Your main objective is to get to the square with an "O".