Unlockable: Hard Mode
Finish the game once. Then, when you select Load Game, hold L1 and R1.

Unlockable: Maximum Mode
Finish the game once. Then, when you select Load Game, hold L2 and R2.

Unlockable: Characters

To unlock the following characters, fulfill the conditions listed…

Byakuya
- Beat Mission 29, accumulate 900,000 points
Gin
- Beat Mission 11, accumulate 1,600,00 points
Izuru
- Beat Mission 11, accumulate 700,000 points
Kisuke
- Beat game twice, accumulate 2,200,000 points
Rangiku
- Beat Mission 11, accumulate 400,000 points
Renji
- Beat Mission 29, accumulate 900,000 points
Toshirou
- Beat Mission 11, accumulate 1,300,000 points
Yoruichi
- Beat game twice, accumulate 2,500,000 points