FlatOut: Head On Codes -

Cheat mode
Select "Extras" at the main menu. Select the "Enter Code" option, then enter one of the following codes to activate the corresponding cheat function. 

1 million credits
Enter GIVECASH as a password.

All cars and 1 million credits
Enter GIEVEPIX as a password.

All tracks
Enter GIVEALL as a password.

Big Rig
Enter ELPUEBLO as a password.

Big Rig truck
Enter RAIDERS as a password.

Flatmobile car
Enter WOTKINS as a password.

Mob car
Enter BIGTRUCK as a password.

Pimpster car
Enter RUTTO as a password.

Rocket car
Enter KALJAKOPPA as a password.

School bus
Enter GIEVCARPLZ as a password.