There is a code to unlock blood and arcade fatalities in the censored SNES version of the game.
Such a code does exist, but only in the Genesis version.
This was the basis of an April Fools' prank in Nintendo Magazine System, which claimed that 'super death moves' were present in the SNES version and could be unlocked by a ridiculously complicated chain of actions that included sellotaping a coin to your cartridge if it had a particular serial number.
There is a playable character named Ermac, a red palette swap of Scorpion.
In tribute to this, Ermac could be fought at the Warrior Shrine in Shaolin Monks during a series of missions, referencing one of the methods to reach him which involved the Warrior Shrine.
This lie stems from a misinterpretation of the ERMACS option on the diagnostic screen, which stands for "Error Macro." Ermac finally appears as a real character in Ultimate Mortal Kombat 3, as a response to this lie.
In Mortal Kombat (2011), Ermac appears a character for Liu Kang to fight in the Story Mode in the first tournament.
There is a certain extra joystick movement that, if performed during Scorpion's spear throw, will cause him to say "Get the fuck over here!"
This eventually occurs in Shaolin Monks (albeit rarely and without the alleged extra combination)
The ability to play as Shang Tsung and Goro.
Goro can be unlocked for play in the Gameboy port. Also, he is available for play in Mortal Kombat Trilogy.
A recently discovered glitch on the SNES allowed the second player to play as Goro (albeit very limited)
Reports of an African-American kickboxer named Nimbus Terrafaux as a hidden opponent.
As an arcade exclusive secret, if you select Johnny Cage and insert a coin while pressing start at the same time, you will play as a superpowered version of him that has his "Green Bolt" move from the original Mortal Kombat, as well as a Shao Kahn-like "Shadow Elbow".
There is a "meathook" finisher that lets you uppercut an opponent onto the chains in the Dead Pool stage.
An uppercut as a fatality on this stage actually does send an opponent into the acid below the stage.
Midway actually added meathook finishers into the Dead Pool stage in Mortal Kombat: Shaolin Monks where you have to uppercut your opponent onto the hooks in order to advance further.
There is a finisher that allows you to uppercut an opponent into the mouth of one of the trees in the Living Forest stage.
This rumor serves as the major puzzle for the Living Forest area in Shaolin Monks.
In Mortal Kombat (2011) the Living Stage fatality was made made into reality where the defeated opponent is thrown into the mouth of one of the trees, they get gobbled up leaving only the legs behind.
Amongst other fake finishers rumoured were the "Animality" (sometimes "Bestiality") and "Nudality".
The Animality would later be implemented in Mortal Kombat 3. Nudalities would never surface in the series proper.
Pressing a certain combination of buttons in front of a specific tree in the Living Forest would lead the player to a battle with Skarlett, a female assassin wearing red (as opposed to Kitana, Mileena, and Jade's blue, purple, and green, respectively).
In Shaolin Monks, Kitana's alternate color swap depicts her outfit as red
Skarlet later became a fully playable character through DLC for Mortal Kombat (2011) as a knife-wielding ninja who utilizes blood in a variety of techniques including morphing into a puddle.
Reptile says "Friendship!" and bows before lashing his tongue out and eating his opponent's head when his Fatality is performed.
There is a special move that transforms you into Kano, a character who was selectable in MK1 but not MK2.
Among the gameplay audits tracked by the game is one "Kano Transformations" which was deliberately added by the developers to trick people into believing this was possible.
There is a new character named Smoke who has cigarettes for fingers.
Smoke is a secret (non-playable) opponent in this game, and is playable in the sequel in cyborg form. He does not have cigarettes for fingers.
Kano and Sonya can be made playable by defeating Shao Kahn with a Double Flawless victory, at which point you character will break their chains. (Kano and Sonya appear chained to posts in the background of Shao Kahn's stage)
In Shaolin Monks, the player can free these two near the end of the game which is followed up with a fight against Kano with Jax assisting the player(s). Winning the battle results in Kano's death and Jax rewards the player with both a health upgrade and a spare health item to use in the final battles.
Kintaro can be unlocked for play via Shang Tsung's morph
Shang Tsung can only briefly change into Kintaro as a somewhat, difficult-to-perform Fatality.
There is a secret character called Pedro, a Mexican fighter who attacks by farting fire.
This was an April Fools' hoax by Computer and Video Games magazine.
There is a special move that allows the character to impregnate one of the female characters. This is said to cause the character to explode after a span of time and make babies appear to come out of the character's belly.
This is only partially true. In the Nintendo 64 version of Trilogy, when the winner performs a Babality, the loser must hold down High Punch, Low Punch, High Kick and Low Kick in which the loser reverts to normal after being turned into a baby and explodes shortly after.
When the face of Dan Forden appeared saying "Toasty" for a very short time, the player should press Select while he was still on screen in order to unlock cyborg Smoke character which could be seen in the character selection screen but could not be selected (SNES version of the game).
Although this is a lie, there is still a password which consists of a combination of buttons, that if entered correctly at the opening screen unlock the cyborg Smoke character.
The lie may have been based on the original method to reaching him in MKII where the player has to press Down and Start when Forden shows up while at the Portal stage.
There is a cheat code to unlock Rain as a playable character in the Arcade version
The character Rain was made as a deliberate farce by Midway for players to try and find him to increase the game's lifespan. He only briefly appears in the Attract Mode and even then, no coding for him actually exists. Despite this, the player was encouraged of his existence by a clue that states 'Rain can be found in the Graveyard'. He is added to the roster of playable characters along with Noob Saibot in the SNES and Sega Genesis/Megadrive ports.
There are special 'Friendships' that were added where the female ninjas would turn towards the opponent and flash them but the player didn't see anything revealing. These were supposed to be a joke referencing nudalities, and were probably the result of confusion with Killer Instinct, where such a fatality actually exists.
The PC and PSX versions featured CGI-rendered endings added more to Reiko's ending. The original version was viewed as a joke to many; the character merely walks through a portal and the ending finishes there. The CGI version shows Reiko at the destination of where the portal led him: a throne. He assumes occupation of the throne and Shao Kahn's helmet descends on his head, identifying him as Shao Kahn. Deception later put this to rest as the Konquest mode revealed that not only are the two completely different characters altogether, but that Reiko was merely obsessed with Shao Kahn by constantly wearing his helmet at times. Both the comics and Shaolin Monks have shown Shao Kahn unmasked, but looks nothing like Reiko.
In another nod to this, Reiko's appearance in Mortal Kombat Armageddon depicted him in strikingly similar attire to Shao Kahn and his ending has the emperor's helmet stuck to his head.
There's a secret character based off of Iron Man that has blades on his hands and looks a little bit like Reptile in a sparkly jade and turquoise Iron Man suit. His name is Reptron. The only way to unlock him is by beating the game with Reptile six times then entering the cheat code "Ironsuitacid".
Belokk was a character created by fellow developer Eurocom as a new character for the game and screenshots of him were even posted. Belokk was supposedly an improved, boss-like version of Shinnok, possessing the moves of every character in the game, even Goro. He was removed from the game for a couple of reasons. He was thought to have been in the final version, as Tanya's portrait in the character select screen can be rotated to reveal a secret character like Cyrax to Sektor or Reiko to Noob Saibot. This effect, however, appears to be merely cosmetic and nothing changes.
There have been several rumors about hidden DC characters who didn't make the cut, and hidden costumes for various characters. The method for unlocking these characters frequently involved insane controller inputs while getting shocked by Captain Marvel at the Rock of Eternity stage, or while standing on the glowing line in one of the split stages.
A Heath-Ledger-looking Joker.
A cartoon "Slade" style Deathstroke.
A Jay Garrick flash.
Black Adam instead of Captain Marvel.
Various different Green Lanterns including Guy Gardener, John Stewart, Kyle Rayner, Kilowog, and even Sinestro. This one usually involved getting perfect-KOed an impractical number of times on the Oa stage.
Crime Syndicate of Amerika versions of Superman, Batman, Wonder Woman, the Flash, and Green Lantern. Ultraman, Owlman, Super Woman, Johnny Quick, and Power Ring respectively.
One 4chan /v/ poster insisted it was possible to escape from Captain Marvel's grip during his shock attack, causing the lighting bolt to strike him instead and transform him into Billy Batson.
There's a way to unlock James Earl Cash from Manhunt as an unlockable character, though he has a more Devil-like look to him: just beat the game with Kano three times and with Jax three times in a row then enter the cheat "StrappedforCash" at the cheat menu.
Apokolips was originally planned to be in the game in a gold and silver costume.