Ghost Recon 2

Unlock Everything:
Enter the following at the main menu: Circle, Circle, X, X
User Cheat by jackcutmore

Medals:

Purple Heart: Get wounded or killed in action.
Bronze Star: Get 15 kills
Silver Star: Get 20 kills
Distinguished Service Cross: Get 25 kills
Congressional Medal Of Honor: Get 30 kills

Invincibility:
Pause your game during a mission, then press L1, R2, L2, R1, Select.

All guns:
Press X, Left, Triangle, Square, X, Select at the main menu.
User Cheat by Snakeeater

All missions:
Press X, L2, Triangle, R2, Select at the main title screen.

Health:
when the title page appears press L1, R2, R1, L2, Circle, Up, L1 to start each level with health and armor which is a whole nother thing of health