Cheat Menu:
At the story screen (when it immediately comes on), press:
high kick, low kick, run, low punch, high punch, high punch, high punch, low punch, low punch.
You will hear OH-MA! to confirm the code. Go to options menu and there will be a red and blue cheat menu.

Freeplay:
At the intro screen, press Down, Down, Up, Up, Forward, Forward, Back, Back.

To play Pong (!):
To play Pong, play 50 two-player matches in a row.

To play Galaga (!):
To play Galaga, play 100 two-player matches in a row.

To play Space Invaders (!):
On the pit stage; when a silhouette goes over the moon, press the Z trigger button...

To play as Khameleon:
Wait for the "story" screen to appear during the game demo mode, then quickly press right-C, up-C, A, B, down-C, up-C, right-C. If you are fast enough , you'll hear Shao Kahn say, "Khameleon." Now Khameleon is a selectable character. To fight against Khameleon, press 3 and Start on the Star Bridge when Toasty shows up.

To play as Human Smoke:
Select Robo-Smoke hold Back and press High Punch, High Kick, Block, and Run. Robo-Smoke go boom, become Human Smoke.

To play as Shao Kahn:
Hold down, low punch and high punch. Must be done in the beginning of the first round on The Rooftop, Pit 3, or Kahn's Cave.
Kahn's Special Moves: Fireball - Forward, Forward, Down, Left Kick; Shoulder - Forward, Forward, High Punch; Upwards Shoulder - Down, Down, Forward, High Kick; Insult - Hold Block, then Up, Up, Run; Laugh - Down, Down, Run; Hammer (Finishing Move) - Forward, Forward, Back, High Punch, then hold Sweep (Back and Low Kick).

To play as Motaro:
Hold left, low kick and high kick. Must be done in the beginning of the first round on Jades Desert, Kahn's Tower, or the Wastelands.
Motaro's Special Moves: Fireball - Hold Left Kick for 3 seconds, then release; Sweep - Back and Low Kick; Grab - Forward, Forward, Forward, High Punch; Teleport - Down, Back, High Kick; Head Rip (Finishing Move)- Forward, Forward, Forward, High Kick (must be close to enemy).

More Options:
At the beginning of the game when the story line is scrolling down, press C-down, B, A. Shao Kahn will say: "Outstanding". When you go to the options menu, there will be a new question mark. You can toggle Khameleon, Smoke, etc.

Unlimited Credits:
At the storyline screen quickly press Down, Down, Up, Up, Right, Right, Left, Left and quickly press Start. If you were fast enough you should get unlimited credits.

Stage Select:
Highlight Sonya on Character Select Screen, press Up and Start. You can then choose a level after choosing a character.

Extra Endurance Matches:
Highlight Kano on Character Select Screen, press Down and Start. This gives you more endurance in one-player mode.

Reverse Babality:
If you get hit with Babality by an opponent, press and hold High Punch, press Low Punch, High Kick, then Low Kick. You still explode, only in multiple stages.

Kombat Kodes
Disable Throws : 1-0-0-1-0-0
Disable Blocking : 0-2-0-0-2-0
No Power bars : 9-8-7-1-2-3
Dark Fighting : 6-8-8-4-2-2
P2 1/2 Energy : 0-0-0-0-3-3
P2 1/4 Energy : 0-0-0-7-0-7
Fight Shao Kahn : 0-3-3-5-6-4
Fight Noob Saibot : 7-6-9-3-4-2
Message Code #1 : 1-2-3-9-2-6
Message Code #3 : 2-8-2-2-8-2
Scorpion's Lair : 6-6-6-4-4-4
Noob's Dorfen : 0-5-0-0-5-0

Thanks to Revolution readers Justin Jaynes, David Reichel, Brian Lee, Matthew Cervantes, Robbie, Aaron, Eric H. Sanchez, Karen Rekowski, and David Van Meter!