No Enemies
Enter RBNL XHGB VGBB LYLD as a password. Only Bosses will appear in the game. Note that while using this code, Levels 5 and 6 will not appear.

Have All Items
Enter QFFF KNRR DDLR XGTQ as a password.

Play as Ultimate Gargoyle
Enter FDQP QRMB FGNH GTKL as a password.

Have All Five Vials
Hold A at the Title Screen and keep that button held while pressing Start to begin a new game. Note: Passwords and options may not be used when using this.

Passowrd for Level 2: BDLK BXPB GHGG FQKL

Passowrd for Level 3: TRTL STGZ FQMF XFLF