Ys III: Wanderers from Ys Cheats
for Genesis

Healing

When the SEGA logo appears, hold Up on Controller Two to activate the cheat. To use it, enter the Status screen and press Up, Down while holding C.

Instant Levels

To do this trick you can either start a new game or used a previously saved one. If you start a new game, buy the short sword, leather armor, wood shield, and an harb. Save the game, TURN THE SYSTEM OFF, then turn it on and go to your status screen. On controller 2 press A, B, C and UP or DOWN to raise or lower levels. This can also instantly heal by raising or lowering a level then putting it back.

Quick Level Gain

In the Alcanio Ruins Go through the first building & through the first two
outdoor screens & back to the begining of the level. Repeat until you are on
the desired level.