Mortal Kombat (Arcade)

Mortal Kombat is the game that excited youths, pissed off senators, and competed with Street Fighter II...all on a budget of $20 and a battered second-hand camcorder.

Unused Sprites
 Goro dying. Perhaps he was meant to turn to stone and shatter like Shao Kahn does when he dies in the sequel?

 Johnny Cage doing some sort of flip or flip kick. He does have a similar move in Mortal Kombat: Deadly Alliance as part of his Karate fighting style and in Mortal Kombat (2011) as a special move. It's possible this was meant as a special move or Fatality.

 Shang Tsung laughing, which may have been meant as a win pose. Shang Tsung does laugh in the sequel.

 Unused sprite of Shang Tsung clapping in the Throne Room background.

 Shang Tsung actually using his sword. He was originally meant to have a Fatality wherein he beheaded his opponent.

Unused Music
This track is used in prototype versions 8.0 and 9.0 when Goro first appears. For whatever reason, the released versions just play the Goro's Lair track again. The track is still in the game, though.

Unused Text
Present in ROM chips mkt-ug12 / mkj-ug12 (interleaved).

Temp Bio Text
Located at, after Sonya Blade's bio text: SANS BIO

Likely a placeholder for characters whose bios hadn't been written yet. If you force the game to load the values for what would be Shang Tsung's and Goro's biographies, this text will be displayed. Since they are bosses and the game won't ever display their bios normally, they probably just plugged in SANS BIO for them.

Old Copyright String
Located at : COPYRIGHT 1987 WILLIAMS ELECTRONIC GAMES INC.

Definitely leftover text from another game.

Unused Intro Text
Text starts at : GORO AWAITS !!

Possible alternate intro text for "GORO LIVES..." ?

Unused Audits & Debug Text
Text for an inaccessible debug menu begins at : CHARACTER ENDINGS CAGE KANO RAIDEN KANG SCORPION SUBZERO SONYA

There are a number of unused audits in the game. Audit text starts at : FRAMEA9 ERRORS GREEN NINJA COUNTER SEC CHIP FAILURE SYSTEM LOCKUPS ILLEGAL OPCODES S TAKEN DOOR SLAMS These were probably for development reference. The "green ninja" is most likely a reference to Reptile.

Ermac
Present in the audit menu (but only in the Y-Unit versions) is a listing for "Ermacs" which, due to being under the Reptile listings, started a popular rumor that Ermac was a hidden character that would be fought/unlocked when certain conditions were met. In reality, "Ermacs" refers to "Error Macros", a log for the developers for when the game crashed unexpectedly...but in the final version the counter can't actually go up and is just for show.

Ermac became a playable character beginning in Ultimate Mortal Kombat 3, with his backstory using the rumor as a base.

Greetings
A list of greetings to various people can be found at HELLO TO.... MOM FRANK SONIA MIKE EIDIE TANIA MATT FIFA SEAN JASON RAMON CLARA DAVE NIGEL MARTHA KENT CHRIS MATTHEW AMY BRIAN LESLIE