Castlevania: Harmony of Dissonance Boss Rush Mode

The Boss Rush Mode is unlocked once you've defeated Maxim in the final battle. It will be accessible from the title screen, which will turn red from the original blue. There are three difficulty levels for the Boss Rush Mode, but you must beat each level in order to unlock a harder one. The difficulty level determines how many bosses you'll have to fight, as follows:

Easy:
Giant Bat
Living Armor
Skull Knight
Golem
Minotaur

Normal:
Giant Bat
Living Armor
Skull Knight
Golem
Minotaur
Devil
Giant Merman
Max Slimer
Peeping Big
Legion (Saint)

Hard:
Giant Bat
Living Armor
Skull Knight
Golem
Minotaur
Devil
Giant Merman
Max Slimer
Peeping Big
Shadow
Legion (Saint)
Pazuzu
Minotaur Lv2
Legion (corpse)
Talos
Death
Death (2nd form)
Cyclops
Dracula
Dracula (2nd form)

Play as Simon Belmont in Boss Rush Mode:
Unlock Boss Rush mode, then press Up(2), Down(2), Left, Right, Left, Right, B, A, Select at the Konami logo.
Select Boss Rush mode to play as the NES version of Simon.

Play as Maxim Kischine in Boss Rush Mode:
Unlock Boss Rush mode, then hold L + R at the Boss Rush menu. Keep the buttons held until the difficulty setting is selected.
You will now control Maxim in Boss Rush mode.

After choosing your mode, you appear in a long corridor. The lamps contain the sub-weapons in this order:
Knife, Sacred Fist, Holy Book, Holy Water, Axe, Cross.

In all the corridors following this, every lamp will contain a large heart with a possible total each time of 30 hearts.