Demon's Crest

No enemies:
Enter RBNL XHGB VGBB LYLD as a password. Only Bosses will appear in the game. Note, levels 5 and 6 will not appear with this code.

All items:
Enter QFFF KNRR DDLR XGTQ as a password.

Play as Ultimate Gargoyle:
Enter FDQP QRMB FGNH GTKL as a password.
Information in this section was contributed by Kenshin.

Super password:
Enter KDGY KRMV DDXR XWKQ as a password for every crest, fire power, potions, Gargoyles, and talisman.
Information in this section was contributed by SpiderRalph.

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.

Hint: Easy boss battles:
On most level Bosses (except big ones like Arma), after you do enough damage to them, using a death spell will then kill them. You have to do this after doing a lot of damage. However, it will not deliver an instant kill as soon as you see them.
Information in this section was contributed by James Solonika.

1. All items collected; for best ending.

Information in this section was contributed by Jesse Smith.