You can use these codes with a Game Genie on an old NES system, or with most emulators that allow the use of Game shark codes. Be careful because some of these have interesting effects on your game!

XSKUILTA	Free Purple Ring
ESKUILTA	Free Blue Ring
OSKUILTA	Free Red Ring
SGAOXK	Caves have hidden entrance elsewhere
SGTOSK	Caves under bushes revealed
OAKOEK	New world map
PGAOSK	New dungeon
TIKAAI	Warp to next screen instead of scrolling
TIKAII	Launch across screen
GGAEXP	People and enemies appear in status bar
YEAOAA	MAKE ALL FILES QUEST 2 FILES
POKEXX	Invisible enemies
POKEXA	Enemies appear in the walls
SULUIS	Enemies only hurt when hit by slash vertically
SULUII	Jabs have no effect on enemies
SUKUIS	Enemies deaths are only one color
GULUIU	Invincibility
LULUIU	Can walk through walls downwards
AVVLAUSZ	No damage for you!
YYKPOYZZ	Create character with 8 Hearts
NYKPOYZZ	Create character with 16 Hearts
SZVXASVK	No Rupy loss when purchasing items
AEVEVALG	Get the items for free, but lose money if you have it
SZNZVOVK	Infinite Bombs