Master code:
Select the "Profile Editor" option at the main menu, then choose
"Unlock Items", and "Cheat Codes". Enter IGIVEUP as a code.
A message will confirm correct code entry.

Fight as K1 or K2 (bosses): Finish the game's story
mode with the difficulty set to hard.
K1 and K2 will be selectable in the Vs. mode.

Level Select:
While playing, hold Down + Start. The game will pause.
Next hold Up and press Triangle, Circle, X, Square.
A number will appear at the left of the screen.
To change levels, press L1 + Select then press L1 +
Start to warp to the selected level.

Ghostball mode:
Press Square(2), Left(2), Right(2), Circle(2) at the title
screen. A message will appear to confirm correct code entry.