Castlevania: Aria of Sorrow

Best Ending hint
Collect all of the ancient books and beat Graham. You will then be taken to a fight against Chaos. Beat Chaos for the best ending.
(Thanks to Orlando@aol.com)

Unlock Boss Rush Mode
Beat the game to unlock Boss Rush mode. It can be found under the "Special" menu.
(Thanks to Orlando@aol.com)

Unlock Hard Mode
Beat the game and get the good ending.
(Thanks to Orlando@aol.com)

Unlock Julius Belmont
Successfully complete the game with a good ending. Then, enter “JULIUS” as a name and start a new game.
(Thanks to OroMln@aol.com)