At the story line screen, press RUN-BLK-BLK-RUN-HP-LP.
You'll hear Shao Kahn say, "Outstanding." Now press
Start and go to the Options screen. You'll see a block
with a blue question mark with the following secret
options: Level Select, Throwing, Unlimited Run,
Bloody Kombat, Smoke, Khameleon. You can toggle these
on and off.
