The following four cheat modes (ordinarily greyed out in the "cheats" menu) are accessible by completing the game on certain difficulty settings, as described below. Please note that you cannot play through the game on King Difficulty until you have beaten the game on Hard ...

Effect	How to unlock
Armour Power	Complete the game on Hard Difficulty
Invulnerability	Complete the game on King Difficulty
Master All Moves	Complete the game on Normal Difficulty
Song of Death	Complete the game on Normal Difficulty