High Definition mode
Before the “Sony Computer Entertainment Presents” screen appears, hold L1 + L2 + L3 + Square + Circle. If you entered the code correctly, the letters on that screen will turn purple. -From: Larry Solinger

Challenge Of The Titans mode
Successfully complete the game to unlock the Challenge Of The Titans mode.

Arena Of The Fates mode
Get a “Titan” rank in Challenge mode to unlock the Arena Of The Fates mode.

Titan mode
Successfully complete the game to unlock the Titan difficulty setting. (more…)