Invincibility [Demo Version] - Before the end of the level, just when the helicopter picks you up, wait about five seconds. Then, go to your action menu by pressing  or  and select "Eject". Press Enter and your character will parachute out of the helicopter. When he lands, you can continue the game and not get killed.

Bonus level - Successfully complete the game with the best ending. Allow the credits to complete and an intermission sequence will begin.

Invincibility - Start your mission and go until you get to the helicopter. Wait a few seconds and jump out of the helicopter. Jump out before they start screaming about the helicopter getting hit. You will become invincible until you go to the Target area and finish the level.

Infinite Save Games - If you need to save more than once in a mission, then you need to delete the old save game file. It can be found in the directory Users\\Saved\Campaigns\1985. ALT-TAB out of the game, make a backup copy (trust me!) and then delete the save file. ALT-TAB back and press ESC to pause the game. You should now be able to save the game again. You can do this as many times as you like. 

Unlimited ammunition - Simply reload before you run out of shots on one clip.

Evac level - Use the following tactic in the Evac level where you have to drive a truck. Go to this grid code to join the Guerillas Fia EA64. On the map there will be a code 113. Drive your truck there. An intermission sequence will appear, then the level will end. You will be a hostage for the Soviets. Stay in the tent on the next level until the Russian that is guarding you dies. Then, go outside and one of the guerrillas will talk to you.