XIII Cheats for XBox
To gain more ammunition kill an enemy when he is reloading his weapon and you will get a full magazine for your weapon.
When you first start the FBI level, immediately after the woman shoots out your cuffs, go to the center of the room with the three computers. You will find the Ubisoft logo acting as a screensaver.
Wait until an enemy reloads his weapon before killing him. Now shoot him before he fires his gun and you will get his full magazine for your weapon.
Enter a new profile,And type in "GOTHI". Then start a new game and press the white button to switch God Mode. Then press up on the D-pad to enable No Clip. By doing this you can walk through walls, fly, and go beyond level limits.