While playing press X + Y + Z.
While playing press A + B + C
Level 02: FWQP Level 03: PLRQ Level 04: SZNF Level 05: TD5S Level 06: J1BT Level 07: K2CV Level 08: N3DW Level 09: M4FX Level 10: X5GZ Level 11: C6HO Level 12: D7J1 Level 13: F8K2 Level 14: FGL3 Level 15: JFM4
While playing press A + B + C.
Type L0SR at the password screen. You get a strange code. Start a new game or load a previous saved game.