|Name of the file: Kill Switch - Author: ANO - [XBOX]|
Pause the game and press Left Trigger, Right Trigger, X, X. When done correctly you'll hear a sound.
Successfully complete the game on the normal or hard difficulty setting to unlock an option that will allow you to pick any level in the game.
When on any level and there are two enemies talking to each other, throw a grenade (for example at the beginning of the Think Like A Gun level). They will not even look to see what it was because they will be distracted.