From the main menu screen, choose the Password Option from the Options menu and input the passwords as shown below:
Here is a list of the secrets you can unlock for beating the corresponding levels with an Excellent evaluation.
This code is the master cheat that unlocks allof the secret codes. First, go to the main menu and select options. Then go to passwords and type in ''ENTREZVOUS'' Then go to send. Enter the passwords again and type ''PORTECLEFS''. Then go to secret codes and all secrets will be unlocked. Civil war mode is every man for himself in missions. The enemies shoot at each other and you. Also, Wacky taxi mode is when you have 1 minute to complete the level and the only way to get more time is to kill.
Simply enter ENTREZVOUS as a password, then LEMONSTRE. To play the level, select 'Panzernacker Unleashed'.