Castlevania Double Pack Cheats - GBA

Cheat Mode
When starting a new game, type in the following codes as your name:

HARDGAME - Hard Mode (HoD)
NOMAGIC - No Magic in Harmony of Dissonance
NOUSE - No items
NOSOUL - No souls
MAXIM - Play as Maxim
JULIUS - Play as julius (after beating the game once with the good ending)

AOS - Extended story
Before you fight Graham, equip the Flame Demon, Succubus, and Giant Bat souls. After killing Graham, the story will continue.

Play as Maxim in Hod Single Player
Beat the Game.

Unlock Boss Rush Mode in HoD and AoS
To obtain Boss Rush Mode in either game, simply beat them with a good ending or better.

Unlock Hard Mode (AoS)
Beat the game with the good ending.

Unlock sound mode in aria of sorrow and harmony of dissonance
To unlock sound mode in the games simply beat the game you want the sound mode for with the good ending:

AoS-sound mode - Beat chaos
HoD-sound mode - Beat dracula