If fighting as player one, choose any male ninja (Reptile, Classic Sub-Zero, Rain, Human Smoke, Ermac, Noob Saibot, or Scorpion) and hold Left + R1 + R2 + Square + Triangle until the fight starts.
Now the credit display will change to 'Freeplay'. If you entered the code correctly, you will hear a sound. At the story screen, press Down(2), Up(2), Right(2), Left(2).
