Skip Opponents
First you must go to the options menu. Then set your controller down and wait until you hear a laugh. Wait ten more seconds and it will go to exit by it self. Then start a tournament pick your fighter. Let the computer beat you then when the continue screen pops up press start on controller 2 but when it asks Mortal Kombat 2 on 2 or 8 player tournament go to Mortal Komabt and press start on controller 1. Then pick your guy and it takes you back to your opponent screen.

8 Lives in Galaxian Mini-Game
Note: a six-button controller is needed to activate this code.
Enable the cheat menu and select "play hidden game". While the intro screen is running hold (X+A+Z+C) . Hold this down until the game starts. You should know the code has worked if you hear a firing sound and see no laser fire on screen. you know have 8 lives .

Advancement
On one of the "Endurance" or boss squares play the game but lose. Right before your opponent kills you, press Start on the second controller. At the Mortal Kombat screen, press Start on the first controller. Choose a character and start a game. When you play you will move above that square. This sometimes works on normal players but sometimes it doesn't.

Note: This trick always works if you select Shao Kahn. You will then play against several different characters endlessly. As a bonus, every time they win they will do a finishing move on you.

A Good Ending
Plug in a second controller, but play a one-player game. When you lose, hold Down on both controllers and your opponent will kill you with a fatality or a brutality.

Kombat Codes

Code Effect
303-606 Bonus Pong game
955-955 Extended fatalities
444-444 Change into random fighter every 10 seconds
044-440 Start with one round won and almost no power
205-205 Fight Smoke
122-333 View character credits
911-911 Computer disables most used button after Round 1
999-995 Combos diabled
010-010 Shao Kahn comments when you throw someone
020-020 Blocking disabled
100-100 Throwing disabled
466-466 Unlimited run
011-971 Healing
494-494 Timer is super fast
987-123 No Power Bars
688-422 Dark Fighting
091-293 Sweeping Disabled
082-771 Disable Throws and Sweeps
033-000 Player 1 half energy
000-033 Player 2 half energy
707-000 Player 1 quarter energy
000-707 Player 1 quarter energy
985-125 Physco Kombat
460-460 Random Kombat
642-468 Game of Galaga
282-282 "No Fear"
123-926 "There is no Knowledge without Power"
550-550 "Go See MK Live Tour"
122-221 "Skunky"
004-400 "Watcha GUN Do"
448-844 "Don't Jump at Me"
688-688 Quick uppercut recovery
969-141 Fight Motaro
033-564 Fight Shao Khan

Play as Human Smoke
Select the robot Smoke on character select screen. Then, before the fight screen comes up, hold High Punch + Low Punch + High Kick + Low Kick. Continue to hold these until Shao Kahn announces the round. (A six-button controller might help...)

Cheat
B,A,Down,Left,A,Down,C,Right,Up,Down (at START/OPTIONS menu).

Different cheats
At the begining when it says start game and options press a,c,up,b,up,b,a and down.Then youl hear shang sung's voice say excellent