These codes all require the 6-button Genesis controller and require that you start a new game, so be sure that an EMPTY save slot is highlighted on the Title screen's Diary menu beforehand. Input one of the codes as listed below on the Title screen, then press the Start button twice; a sound effect will play if entered properly.
|Password||What it does|
|Down+Right, A, Z||Unlock Area Select (Hold the Mode button as you open the Diary menu during gameplay) and Dialog Viewer (Hold down X and Y during gameplay, then press either A or C; keep X and Y held down and talk to any NPC)|
|Up+Right, A, Y||Full Inventory & Upgraded Stats|
|Down+Left, A, B, Z||View Ending|
If you have the 6-button Genesis controller, you can instantly switch between your knife and currently selected weapon (w/o opening the weapons menu as normal) simply by holding down the Mode button and pressing B.
First acquire the Key of Time and Space by defeating the Mega Serpent at the Wall Fortress, then go to the seashore at the lower west portion of the map. Find the invisible portal around this area using Shade's Doppelganger, then use the Key to warp to the secret island seen in the upper west part of the map.