To de-activate the code, press the same keys again. When you enter a code successfully, a chime sounds. Note that you can enter more than one code at a time (though only one weapon code at once), and you can enter codes during cut scenes.
Finally, to activate a code, press the keys indicated during game play. Then unlock each individual code by completing levels in Time Trial. Sorry.) After completing the Bolivia Redux level, the Cheat Codes sub-menu is accessible by selecting Extras > Special > Cheat Codes from the main menu.
Cheat codes can only be unlocked by first beating the game.
