Various cheats
     Start  the  game and get in control of the player or vehicle. The
cheats will only work when the movement keys are usable.

Now just type in the code on your keyboard:

Cheat code:        Effect:
trickedout         Upgrade all weapons by 1 level
freeman            Get 5 more lives
boostershot        Recover (life) energy faster
bombsaway          Get 20 more grenades
microwave          Get 20 more nukes
fastforward        Skip to the next Zone (there are 5 Zones in total).

     Note  that  the game will know you are cheating and not award any
Medals at the end of a Level.