The initial release of the arcade version features unused character biographies for the game's playable cast. These biographies are facetious in nature, for instance claiming that Shinnok was an ex-model for the Bicycle brand of playing cards and that Scorpion's mission in life is to scold a friend for punching him when he was a child. The joking nature of these biographies likely contributed to their disabling in the original build and outright removal from the game's code in subsequent updates. Examining the biographies through hacking the game shows that two of them are unfinished. Fujin is referred to as "Windgod" and Noob Saibot's biography is mostly recycled from Raiden's, with the only original portion being the cut-off opening line.

There is an unused Skull stage that can only be accessed by using Gameshark code 800FE55B 000A. At first the stage will appear black, but pausing and selecting "Restart this Match" will get it to appear properly.

Stage is largely a flat, circular arena with a unique texture painted on the ground. The skybox consists of an image of a skull stretched over the arena, with flames lit behind it. The stage also has some trouble loading the proper music from round to round.

The unlockable character skin Meat got its name from a text posted on a website for Mortal Kombat IV's arcade promotion that read "Meat lives!" and the name was made official by later strategy guides. Despite being a mere alternate costume in Mortal Kombat IV, Meat made a canon appearance as a character in Mortal Kombat Deception and was eventually playable in Mortal Kombat Armageddon.

It was originally intended for Kitana to appear as a fighter. Her color palette was swapped to yellow and thus created Tanya. While Kitana's model and textures were removed from the Playstation release, leaving only her moveset in the code, she is still fully functional in the N64 and PC releases, and can be accessed with a GameShark code or patch.