Invincibility
Pause game play, then press [L1], [R2], [L2],
[R1], [Select].
Mission select
Press [X], [L2], [Triangle], [R2],
[Select] at the title screen.
All special features
Press [L1], [L2], [R1], [R2], [X],
[Select] at the title screen.
12 person online play
Enable the "Online voice chat" code and wait
for the drum roll to stop. Then, press [L1]x3, [R1]x4.
You will hear another drum roll to confirm correct code entry.
If you host games, you should worry about lagging on small maps.
If you can only join rooms you will have to enable this code to
see the host's room. You will also have to change (on the "Join"
menu) the minimum players to one and maximum players to twelve.
This code will allow you to go past the original maximum of eight
to twelve. Note: Enabling this code may freeze your main menu
sometimes. If this happens, restart your PlayStation2.