Fighting Force 64 

Cheat mode 
At the title screen:
hold L + Z + C-Up + C-Down.
If you entered the code correctly, the game will automatically go to the character selection screen. 
Press C-Left or C-Right to select a level. You will automatically begin with 99% invincibility.

Extra money 
Repeatedly roll against a wall until money appears.

Hidden weapons 
The following objects may also be used as weapons:
Totally destroy a car, then Smasher can pick up the engine and use it as a weapon. 
Destroy the airplane at the Airbase to use its gun. 
Destroy the two large black structures found in the Hovercraft level to get a flare gun. 
Destroy the police car in the Car Park level to get a rocket launcher.