Just as Street Fighter II Champion Edition allowed players to fight as the four unplayable characters of Street Fighter II, Mortal Kombat Champion Edition allows players to fight as the three unplayable characters of Mortal Kombat: Reptile, Goro and Shang Tsung!!

The three hidden characters are accessed by inputting special codes on the select screen.

Play as Reptile:
On the character select screen, hold select while selecting Sub-Zero.

Play as Goro:
On the character select screen, hold select while selecting Johnny Cage.

Play as Shang Tsung:
On the character select screen, hold select while selecting Liu Kang.

Move List:

Reptile:
Freeze: Down, Forward + LP
Spear: Back, Back + LP
Slide: Back + LP + LK + Block
Teleport: Down, Back + HP

Fatalities:
Ice Shatter: Foward, Down, Forward + HP
Toasty: Up, Up (Hold Block for easier time).

Note: As of V2.0 can access both Scropion and SubZeros movesets at all times without needing to manually change stance.

Goro:
Punch and Grab: HP(Close)
Fireball: LK
Stomp: Up
Taunt: Back OR Down

Shang Tsung:
Fireball: Up OR Down
Morphs:
Johnny Cage : HK
Kano: HP
Raiden: LK
Liu Kang: LP
Scorpion: Select (Hold) + HK
Sub-Zero: Select (Hold) + HP
Sonya: Select (Hold) + LK
Goro: Select (Hold) + LP
Random Morph: R (when not already morphed)
Random Morph + Attack: L (when not already morphed)
Shang Tsung : L (when morphed)