Galaxian 3 cheats and cheat codes for Playstation

Ghost player (duplicate yourself)
Enter to the play record screen and enable that feature. Begin a new
game and play as far as possible. Go to the gunner battle option and
push Right, Right to choose the "Ghost" option. Begin another game
to have your self as a partner.

Enable Debug mode
Push L1, R2, R1, L2, Up, Down, Up, Down while the Namco logo flying
on the screen.