The first three “Mortal Kombat” arcade games have secret menus, according to a YouTube user—20 years after the games were released.
The uploader, YourMKArcadeSource, who goes by the name Mike, used a series of button inputs, showing the menus in “Mortal Kombat” 1, 2, and 3, as well as “Ultimate Mortal Kombat 3.”
He said in the Feb. 21 video that the secret menus were only discovered in the past week or so, meaning that these menus have been “dormant” for 20 years—despite the massive popularity of the fighting games.

YouTube