Cheat List:
Here are the codes you'll need to enter. Once you become familiar with the code-entering mini-game, these instructions will make more sense. Start a new game, and select "Cheat". Then enable code-entry by hitting Red, Blue, Yellow, Red, Blue, Yellow, and then the center pedestal with a downward thrust. You should hear a chime.
Next, select a code from this list and enter it. Hit the gems in order and then check in with a downward thrust to the center pedestal. If you screw up, hit the center pedestal to clear the slate. If you enter the code correctly, you should hear the familiar Ys item acquisition fanfare.
Classic mode in Japanese = Yellow, Yellow, Red, Red, Red, Red, Blue, Center
Konami mode in Japanese = Yellow, Red, Red, Red, Red, Blue, Center
Item/Tool Limit Increased = Yellow, Yellow, Red, Red, Blue, Blue, Yellow, Red, Pedastel
Items Cost 50% Less = Yellow, Yellow, Blue, Blue, Red, Red, Red, Yellow, Yellow, Yellow, Red, Red, Blue, Blue, Pedastel
Level 10 Cheat = Red, Blue, Blue, Red, Red, Blue, Pedastel
Level 20 Cheat = Red, Blue, Blue, Red, Red, Blue, Blue, Pedastel
Level 30 Cheat = Red, Red, Blue, Blue, Red, Red, Blue, Blue, Pedastel
Level 40 Cheat = Red, Red, Blue, Red, Red, Blue, Blue, Yellow, Pedastel
Level 60 Cheat = Red, Red, Blue, Blue, Yellow, Yellow, Red, Red, Blue, Blue, Yellow, Yellow, Pedastel
Max Out Blirante Sword = Blue, Blue, Yellow, Yellow, Yellow, Red, Blue, Red, Red, Red, Yellow, Yellow, Pedastel
Maxed Out Ericcil Sword = Blue, Yellow, Yellow, Red, Red, Red, Blue, Blue, Blue, Red, Red, Yellow, Pedastel
Maxed Out Livart Sword = Blue, Blue, Blue, Yellow, Yellow, Red, Blue, Red, Red, Yellow, Yellow, Yellow, Pedastel
All three Swords Maxed Out = Blue, Yellow, Red, Blue, Blue, Blue, Red, Red, Red, Yellow, Yellow, Yellow, Blue, Yellow, Red, Pedastel

Game Mode/Movie Codes:
Unlock All Clear Modes = Red, Red, Red, Red, Blue, Blue, Blue, Blue, Yellow, Yellow, Yellow, Yellow, Blue, Blue, Yellow, Yellow, Red, Red, Pedastel
Classic PC Mode (Japanese dialogue) = Yellow, Yellow, Red, Red, Red, Red, Blue, Pedastel
Classic PC Mode (English dialogue) = Yellow, Yellow, Red, Red, Blue, Pedastel
Konami PS2 Mode (Japanese dialogue) = Yellow, Red, Red, Red, Red, Blue, Pedastel
Max Level Mode (Japanese dialogue) = Yellow, Yellow, Red, Blue, Pedastel
Beach Movie (JAP Voice, JAP Sub) = Blue, Red, Red, Yellow, Pedastel
Beach Movie (ENG Voice, JAP Sub) = Blue, Blue, Blue, Red, Yellow, Pedastel
Beach Movie (JAP Voice, ENG Sub) = Blue, Red, Yellow, Pedastel
Napishtim Wasted Movie (JAP Voice, JAP Sub) = Blue, Red, Yellow, Red, Red, Blue, Yellow, Yellow, Pedastel
Napishtim Wasted Movie (ENG Voice, JAP Sub) = Blue, Red, Yellow, Red, Red, Blue, Yellow, Yellow, Yellow, Pedastel
Napishtim Wasted Movie (JAP Voice, ENG Sub) = Blue, Red, Yellow, Red, Red, Blue, Yellow, Yellow, Yellow, Yellow, Pedastel
Ohla Movie (ENG dialogue) = Blue, Blue, Blue, Blue, Blue, Yellow, Yellow, Yellow, Red, Blue, Yellow, Yellow, Red, Red, Red, Pedastel
Ohla Movie (JAP dialogue) = Red, Red, Red, Red, Red, Blue, Blue, Blue, Yellow, Red, Blue, Blue, Yellow, Yellow, Yellow, Pedastel
Ohla Movie (Flute) = Blue, Blue, Red, Yellow, Pedastel
Prologue (JAP Voice, JAP Sub) = Blue, Yellow, Red, Pedastel
Prologue (ENG Voice, JAP Sub) = Blue, Blue, Blue, Yellow, Red, Pedastel
Prologue (JAP Voice, ENG Sub) = Blue, Blue, Blue, Blue, Yellow, Red, Pedastel
Opening Movie = Red, Blue, Red, Pedastel
Opening Movie (English dialogue) = Blue, Blue, Yellow, Red, Pedastel
Romun Fleet Entrance = Blue, Red, Yellow, Red, Red, Yellow, Blue, Pedastel
Romun Fleet Entrace = Blue, Red, Yellow, Red, Red, Yellow, Blue, Blue, Blue, Pedastel
Romun Fleet Destroyed = Blue, Red, Yellow, Red, Red, Yellow, Red, Red, Red, Pedastel
Romun Fleet Destroyed = Blue, Red, Yellow, Red, Red, Yellow, Red, Pedastel

Story/Intermission Session Codes:
CG sequences only = Yellow, Pedastel
Anime sequences only = Yellow, Yellow, Pedastel
JAP Voice, JAP Sub = Red, Pedastel
ENG Voice, ENG Sub = Red, Red, Pedastel
ENG Voice, JAP Sub = Red, Red, Red, Pedastel
JAP Voice, ENG sub = Red, Red, Red, Red, Pedastel

Unlock Crevia Omake Image:
Clear the game once to unlock Nightmare level of difficulty. Clear the game on Nightmare difficulty to unlock a picture of Crevia during the ending credits.