Cheat Mode
Save a game to a back up file and patch byte 18 to a non-zero value and you know have these cheats at your disposal:
ARROW KEYS - Move very fast over any terrain
B - Summon Gold Swan
R - Rescue Princess
= - Display Coordinates
F9 - Increase time by one hour
F10 - Location in coordinates
Unlimited Items
To obtain an unlimited number of items, approach an item and before continuously tapping T before pressing Space.
Unlimited Keys
Entering a dungeon or cave and save the game. Move through your location until you run out of keys. Restore the game to resume with the doors remaining open and a new set of keys.
Unlimited Bravery Points
Jump on the turtle and continue to attack it.
Increased Luck
To increase your luck to 65 first locate the Sorceress on the island with the Crystal Castle. Then use the "Ask" command several times and you will gain luck.