Bonus sailor costumes/outfits
Complete a level with an "S" rank to unlock a bonus sailor costume.

So Long! Round Earth! cinematic
Intentionally lose against the final countdown Boss to unlock the So Long! Round Earth! cinematic for purchase.

The Taste of Victory cinematic
Defeat the final countdown Boss to unlock The Taste Of Victory cinematic for purchase.

Cheerleader costume/outfit A
Complete all the cheerleader blocks in the Messy Park level to unlock the Cheerleader costume/outfit A.

Badtz-Maru
Win the game with the good ending and unlock Badtz-Maru's profile. Start a new game to have the option to play as Badtz-Maru.

Alternate title and loading screens
Set the system date to any day in November to get Hello Kitty birthday themed title and loading screens.

Cheerleader costume/outfit B
Unlock Cheerleader costume/outfit A, then defeat all the cheerleaders again in the Messy Park level to unlock Cheerleader costume/outfit B.

PS2 Cheats for Hello Kitty: Roller Rescue

Hello Kitty: Roller Rescue cheat codes

Hello Kitty: Roller Rescue cheats