Enter the Original Music and Expert Mode codes in order. If you did it right you'll hear a tone and 9 lives will appear.
At the title screen, press Up, Up, Down, Down, Left, Right, Left, Right, B, A. You should hear a chime if the code was entered correctly. A new difficulty setting will appear on the Options screen.
On option screen play BGM (Background Music) 05 and play SE (sound effects) 073. Make sure that these music settings are set when you leave the options screen. Press start to start the game. When your standard weapon is powered up to level 4, you will
hear the old Castlevania Music until you get hit.
Passwords from Konstantin Trunov
This set of passwords will get you through the game as Eric in Easy mode. In the table below, 1=eagle, 2=axe, and 3=magical ball.