After you start a mission goto pause menu. At the pause menu press this combo:
insert, insert, delete, insert, delete.
this works in BA1 and BA2.
BA1 you will get message at top saying "increase damage". Then resume game and stompem.
BA2 This adds cheat console to pause menu.Then type "trigger_damage" to recieve a success message on screen. Then just resume game.
Type "cheat_victory" to pass the lvl you are on.

Make sure NUM LOCK is off if insert or delete share number pad button on your keyboard!!!

In BA1 (PC version) a combination of quickly pressed INSERT and DELETE keys - can make GOD MODE Active (and Deactive) - try it :-)

Does anyone know how do you do a cheat for XB360. I need to advance to the next mission - always stuck at the NAfrica photo mission - so frustrating. Appreciate your advice. Thanks