Finish the game as Alucard with 180% or more and have a obtain a clear save.
Unlockable: Alucard with Axelord Armor
Enter the name AXEARMOR.
Unlockable: Play as Richter
To play as the character Richter in the Xbox360 version of the game, beat the game once with Alucard (with at least 180% of the game complete), then start a new game in a new slot, with RICHTER as the characters name.