Debug mode: 
Press L1, R2, R1, L2, Up, Down, Up, Down when the 
Namco logo flies on the screen. 


Ghost player: 
Enter the play record screen and enable that feature.
Start a game and play as far as possible. Then, enter
the gunner battle option and press Right(2) to select
"Ghost". Start another game to have your self as a 
partner.