Crystalis is a top-down action RPG in which players assume the role of a character named SNK (if the player doesn't assign him a name, that is) who is tasked with collecting four elemental
crystals swords to save the world.
During the game hold A + B on Controller 1, then by pressing A on Controller 2 you can cycle through 16 predefined places of the game.
Invulnerability, All Items, Free Walk
In the Japanese version, hold A + B on Controller 1, then power off and on again the console (this doesn't work if you just reset the console). Now, during the game, press Start to enter the status screen. On Controller 2, press A to enable the super fast movement, press any D-Pad button to enable the invulnerability and add all items, equipment and add an extra 255 MP.
In the US version this feature is disabled, but you still can re-enable it using the Game Genie code XTKLVYAV.
The Game Genie code AXEPNEGG in the US version re-enables some kind of a shop debug routine, which allows you to buy some special items instead of the normal ones.