666 - Play as Smoke.
1000000 - Play as Motaro and Shao Kahn in 2 player mode
1995- Transparent players
831- Shadow Players
9966- Players face wrong direction
4000- Turbo mode
603015- Slow mode
8888- Wide players
1111- Thin players
12345- Tall players
54321- Short players
4862222- Block is bad

The following is a key for the Code Bar on 2 player mode.
{Key}:
0=Dragon
1=MK
2=Yin Yang
3=3
4=Question Mark
5=Lighting Bolt
6=Goro
7=Raiden
8=Shao Kahn
9=Skull

Use the above key and the codes below for pure cheating fun:
100100- Throws disabled
020020- Blocks Disabled
987123- No Power Bars
033000- Player 1 Half Energy
033000- Player 2 Half Energy
707000- Player 1 Quarter Energy
000707- Player 2 Quarter Energy
688422- Dark Combat
642648- Galaga
101000- Player 1 Healing Enabled
000101- Player 2 Healing Enabled
303303- Both Players Healing Enabled
202000- Player 1 Weaking Enabled
000202- Player 2 Weaking Enabled
404404- Both Players Weaking Enabled
552000- Player 1 Takes Double Damage
000552- Player 2 Takes Double Damage
552255- Both Players Take Double Damage
239494- Sweeping Disabled
972279- Timer Disabled
348279- Timer Slow
978243- Multi-Powers
969141- Winner Fights Montaro
769432- Winner Fights Noob Saibot
033564- Winner Fights Shao Kahn
205205- Winner Fights Smoke
282282- No Fear appears on screen
123926- No Knowledge That Is Not Power appears on screen
987666- Hold Flippers During Casino Run appears on screen

Thanks to Revolution readers Abner J. Pastoll, Keith A. Bruce, Van A. Atchley Sr., Jose Guerrero, Adriana Casella de Vainer and Codefreek Ben Shotts!!