Unlock Boss Rush Mode:
When you have successfully completed the game enter a warp room to access Boss Rush mode.

Unlock Easter Island Statue:
To get a Moai statue worth 5,000 Gold you must have a saved game file from Castlevania: Lament Of Innocence on your 'Memory Card'.

Sound Mode:
After beating Boss Rush Mode, the music box should appear in the warp room. With this item, you should be able to access the Sound Mode Option to play various music from the game.

Moebius Brooch:
Once you beat Crazy Mode, the Moebius Brooch will be available in the shop. Equipping this item allows you to do special moves without using hearts.

Moai Statue:
Have a Lament of Innocence save file on your Memory Card. Trevor Mode:
After beating the game once, if you start a new game and put @TREVOR as your name, you'll start the game as Trevor Belmont.

Crazy Mode:
After beating the game once, if you start a new game and put @CRAZY as your name, you will start the game at a higher difficulty setting.