Enter NODEGOSOOOOOOO as a password. Note: Enter MODE FOR OOOO OOO in Japanese version of the game.
Disable door noise
Enter RMAYTJEOPHALUP as a password. Note: Enter PLAY THE ONGA KUN in Japanese version of the game.
Full life
Hold II when using a potion after dying.
Last Quest
Enter the following password to start with all the necessary transformations and items to enter the final castle: W0CV 5ATV KYR1 SV
Secret weapons store
Enter the house with a well in the first village. Fall down the well, and turn left towards the exit door. Place your character on that door, jump directly up, then hold Up while in mid-air. Enter the hidden door that appears above the exit door.
Super password
Enter 3WSURYXZY763TE to start with advanced items and abilities.
Ultimate password
Press Run on the title screen, select Continue and then select Password.
Password - Effect
3ZHURYNZY726VH - Start as Hu-Man with 8 hearts, all equipment, all transformations unlocked and only the final dungeon to beat.