Successfully complete the game on any difficulty setting to unlock a bonus mission.
Cheat mode
Enter reb00 as a profile name. Note: Your score will remain at zero while this code is in effect. All missions will now be unlocked. Select a mission. Press Start to pause game play. A new "Cheats" option will now appear. Select it to enter a menu where the following cheat options can be toggled on or off: "God Mode", "Infinite Ammo", "Infinite Projectiles", "Silent Mode", and "Invisible Mode".
Easy kills
Walk around with your machine gun to easily kill opponents in close combat. However, if you see a sniper at a distance, press R3 to quickly use your sniper rifle.
Exploding bullets
Enter Panzer as a profile name.
Exploding rats
Enter Ratbomb as a profile name. Shoot rats to make them explode. Note: Your score will remain at zero while this code is in effect.
Make your rounds silent
Enter Stealth as your profile name.
Third person view
Hold R2 until the camera icon appears in the top right corner. Press Up or Down to zoom the view in and out.