All Skills Mode
Clear the game with Leon once and save that game. Start a new game on another slot and enter the name @LLSKILL. Leon will have all his skills when he begins the game.
Unlock Jade Mask Item
Clearing the game will unlock the Jade Mask for sale at the shop.
Unlock Mobius Brooch Item
Clearing the game on Crazy Mode will unlock the Mobius Brooch in the shop.
Unlock Sound Test
Clear the game once with any character and save that game. The Music Box will be available for purchase in Rinaldo's shop for all future games (you only need to buy it once and save the purchase to that game).
Unlock Boss Rush Mode
Clear the game with any character and save that game. That game's character may head back to the stage select room and opt to try Boss Rush Mode, that is a time attack mode against all the bosses in the game in the order they appear in the Encyclopedia.
Unlock Crazy Mode
Clear the game with Leon once and save that game. Start a new game on another slot and enter the name @CRAZY. Crazy mode is much harder than the normal game, and Leon starts with a defence of zero.
Unlock Joachim's Game
Clear the game with Leon once and save that game. Start a new game on another slot and enter the name @JOACHIM. Joachim's game is played differently, and the character has no access to any weapons, armour, or health restoration items.
Unlock Pumpkin Game
Clear the game with Joachim once and save that game. Start a new game on another slot and enter the name @PUMPKIN. The Pumpkin game starts the character off with all skills and the Vampire Killer, as well as increased stats. However, there are no subweapons available other than the initial subweapon.
Fire Whip
First, go to the Anti-Soul Mysteries Lab second floor and find the room with the moving platform. Follow it until you get to the second platform on the right. After jumping over the platform, look for two yellow poles. Hook over the two poles. On the upper side, you can find the monster named Flame Element. Defeat him and he will give you the Fire Whip.
Duplicator Glitch
There's a way to duplicate your items. Enter the castle and head to the door that leads to the Save Room and the room to the other 5 stages. In the hallway near the Save Room, look on the carpet for a green spot of color. Go stand on it, facing the window and open up your subscreen and go to your item list. By scrolling through your item list each item mysteriously increases by one.
Duplicator Glitch #2
There is a second spot inside the Pagoda of Misty Moon where items can be duplicated (again). On the second floor hallway, stand near the second circle design on the carpet (on the map, it will be near the east side of the stage). Press START to enter the item screen and glitch away.
Duplicator Glitch #3
The hallway outside the VI Stone room allows items to be duplicated through the start menu (see Duplicator Glitch #2).