Cheat mode
Pause the game and select the "Settings" option. Then, select the "Cheats" option and enter one of the following codes to unlock the corresponding cheat option, which can then be toggled on or off:

Invincibility
Enter "IRONMAN" as a code.

Indestructible cars
Enter "ROLLBAR" as a code.

All vehicles
Enter "CARSHOW" as a code.

Free garage
Enter "TOOLEDUP" as a code.

Infinite nitro
Enter "ZOOMZOOM" as a code.

All weapons in era
Enter "GUNRANGE" as a code.

Infinite ammo
Enter "GUNBELT" as a code.

Weak cop cars
Enter "KEYSTONE" as a code.