HIDDEN OPTIONS
On the Title Screen, choose Options. Highlight Continues and hold Run and Block (C-Left and C-Down are the default buttons for Run and Block) until a special options menu appears. To exit the menu, highlight Exit and press the A Button.
Options available to change:
Endings. Choose between On or Off. Default is Off. If you choose On, the game will automatically end after defeating the first Character in Arcade Mode and you can view the ending.
Fatalities 1. Choose between On or Off. Default is On.
Fatalities 2. Choose between On or Off. Default is On.
Level Fatalities. Choose between On or Off. Default is On.

HIDDEN CHARACTERS
There are several hidden kombantants in Mortal Kombat 4. To access them, select HIDDEN on the character select screen, then do as follows:
NOOB SAIBOT
After entering Hidden on the character select screen, press Up, Up and Left (the cursor will be on Reiko) and then press Run and Block together.
GORO
To Play as Goro, select Hidden on the character select screen, then press Up, Up, Up and Left (the cursor will be on Shinok). Press Run and Block together to play as Shinok.
MEAT
To play as Meat, you'll have to go to "Group Mode" and play as every character, and win every match. After you finish playing, pick any character, but when the match starts you will be playing as Meat. Meat has all the moves of the character that you chose.

Easier Goro/Noob Saibot (two player noob)
To get Goro and Noob Saibot a lot easier go to hidden hold down RUN then move to Shinnok (Goro) or Reiko (Noob Saibot), (to comfirm hold start and press any button) then press BLOCK! you should have your secret character..
To Get TWO PLAYER NOOB do exact same code but with two player (only works with noob saibot).
If done right both players should have noob saibot!

Spike Faced Shinnok
You have to beat the game with Shinnok then
not you but the RED Shinnok's face will be spiked!

Beat Goro very easily.
In order to beat Goro very easily, you'll have to be certain characters.
Quan Chi: Repeatedly do the Tele-Stomp.
Rayden: Reapeatedly do the Torpedo
Liu Kang: Pull out original Dragon Sword and do repeated High Slashes. This can be done by tapping High Punch repeatedly.

Different costumes
At the "Choose your fighter" screen go to any character hold start and tap A and you'll look as the second player but if you do it 2 times on either Raiden,Jax,Reptile, or Liu Kang they'll have totaly different costumes and if you do it 3 times on Johnny Cage or Kai they will to

costume change (actual)
To change a persons costume you hold down start and press the R button. then it would make a sound and the character will change into a ying yang and back. then the costume changes. here are some. sonya 3 starts and R= a pink sonia without a hat. twice would be a a red sonya with a hat.

Secret Characters' Moves
So, you've uncovered the code to be Goro and Noob Saibot and you're still losing. Why? Their moves are not listed anywhere! What follows is the moves list for Goro and Noob Saibot.

Noob Saibot:

Fireball: D, F, LP
Teleport: D, U Slam: BL
Air Fireball: D, F, LP (in air)
Weapon: F, F, HK (Scythe)
Air Throw: Push Block while in air next to opponent

Goro:

Super Kick: B, B, HK
Fireball: F, B, HP
Tele-Stomp: F, F, B, HK
Super Uppercut: D, D, HP
Super Smack: F, F, HP

Cheat Codes
Enter one of the following codes to activate the corresponding effect.

What it // Does Code
One-hit win 123 123
Noob Saibot mode 012 012
Red Rain (On the Rain stage) 020 020
Explosive Kombat 050 050
Drawn weapons can not be lost 002 002
Disable throws 100 100
Disable max damage 010 010
Disable throws and max damage 110 110
Random weapon appears 111 111
Start with random weapon 222 222
Start with weapons drawn 444 444
Many weapons 555 555
Silent Kombat 666 666
Big heads 321 321
Fight in Goro's Lair (Spike Pit) 011 011
Fight in The Well (Scorpion's Stage) 022 022
Fight in Elder God's (Blue Face) stage 033 033
Fight in Tomb Stage 044 044
Fight in Rain Stage 055 055
Fight in Snake Stage 066 066
Fight in Shaolin Temple 101 101
Fight in Living Forest 202 202
Fight in Prison (Fan Stage) 303 303
Fight in Ice Pit 313 313

Fatalities

Johnny Cage:Torso Rips;f,b,d,d+hk(close)
Head Decapitate:d,d,f,d+bl(close)

Fujin:Crossbow death;rn+bl 7 times(mid screen)
Whirl Wind Death:d,f,f,u+bl(mid screen)

Jarek:heart rip:f,b,f,f+lk(close)
eye Laser:u,u,f,f+bl(mid screen)

Jax:arm rip;hold lk,f,f,d,f release lk(close)
Head crush;b,f,f,d+bl(close)

Kai:Body rip;u,f,u,b+hk+bl(close)
head shot;u,u,u,d+bl(mid screen)

Liu Kang:dragon;f,f,f,d+bl+lk+hk(mid screen)
skeet shooting;f,d,d,u+hp(close)

Quan Chi:leg rip:hold lk,f,d,f,release lk(close)
mimic:u,u,d,d+lp(1/2 away)

Rayden;body shock;f,b,u,u+hk(close)
staff shock;d,u,u,u,+hp(close)

Reiko;torso kick;f,d,f+bl+lp+lk+hk(close)
stars of death;b,b,d,d+hk(mid screen)

Reptile;face eat;hold lp+hp+lk+hk then u(close)
acid spit;u,d,d,d+hp(mid)

scorpion;fire breath;b,f,f,b+bl(mid)
scorpion;b,f,d,u+hp(close)

Shinnok;hand clap:d,u,u,d,bl(close)
hand from hell;d,b,f,d+bl(close)

Sonya;kiss;d,d,d,u+rn(mid)
body split;u,d,d,u+hk(1/2 screen)

Sub-zero;head rip;f,b,f,d+hp+bl+rn(close)
freezind;b,b,d,b+hp(mid)

Tanya:kiss:d,d,u,d+hp+bl(close)
Neck twist;d,f,d,f+hk(close)