Unlock 2 extra stages [PS2 Cheat by:Smurf]
Win the game on any difficulty level with a rank "D" or above to enable the versus option on the main menu.
Win the game a 2nd time to unlock the remaining 2 orbital frames and 2 battle levels in versus mode.

Versus mode
Win the game on any difficulty setting to unlock versus mode with five frames and most stages. Win the game on any difficulty setting twice to unlock the remaining 2 frames and stages.

To unlock Versus Mode the easy way, press CIRCLE, X, RIGHT, LEFT, RIGHT, LEFT, DOWN, DOWN, UP, UP at the title screen. If you entered it correctly, you will hear a sound and "Versus" will appear at the main menu.

Full health and ammunition [PS2 Cheat by:Luggs]
[Pause Game] and press L1(2), L2(2), L1, R1, L1, R1, R2, R1. *** Each time this code is used your level will go down by one.

Different ending music
Win the game on each difficulty with an "A" rank on all five rescue missions.

Invincibility [PS2 Cheat by:Gez]
At the begining screen enter: L1x5 R1x3 start and select.
please note you do not have to enter these cheats quickly so take your time!!!

PS2 Cheats for Zone of the Enders

Zone of the Enders cheat codes

Zone of the Enders cheats