You can unlock all modes in the Nintendo DS game Castlevania: Order of Ecclesia by taking the following steps.
Albus Mode: Finish the game after saving all villagers.
Boss Rush Mode: Finish the game after saving all villagers.
Hard Difficulty: Finish the game once.
Hard Mode Level 255: Finish Hard Mode Level 1. OR Connect to Castlevania Judgment (on Wii due November 18th, 2008).
Sound Test Mode: Finish the game after saving all villagers.
Boss Medals tip: When you’re in a boss fight, you can get a medal if you don’t get hit at all. When you’re successful in avoiding hits, then after the fight a treasure chest will appear from the ground to give you that boss’ medal. Each boss has their own medal, which can only be earned during that boss fight.