Instructions
Win two out of three rounds in order to set the conditions to perform fatality moves. Wait for the announcer's prompt to "Finish him."
Take two steps back from your staggering opponent if you are within sweeping distance. Take five steps back if you are far away so you are positioned at the other end of the arena. If close up, take one step back from your opponent.
Press the "L" button at the top of your controller before entering the fatality code.
Enter the fatality code. You must enter the exact code for your character or the fatality will not register. For example, to perform a fatality for Nightwolf press the joystick back, forward, back, forward and then hit the square key to execute and finish off your opponent. For a complete list of character fatality codes, check out the resources for a link to Gamespot's cheat page for "Mortal Kombat Deception."