Using Kombat Kodes (six digit numerical codes in sets of three, specified by Mortal Kombat iconographies) on the VS. character screen before a match, several messages can be conjured on screen when the match has begun. Several of these messages are developer messages and references to other games:

•999-999 = Displays a message indicating what version revision is being played.
•550-550 = Displays the message: "Go see the Mortal Kombat Live Tour!", advertising the 1995 martial arts theatrical stage show of the same name.
•122-221 = Displays the message: "Skunky! - E.F." which assumedly is an inside joke from a developer playing on the "Toasty!" gag by programmer Dan Forden.
•987-666 = Displays the message: "Hold flippers during Casino Run". This is a reference to Jack*Bot, an arcade pinball cabinet produced by Williams Entertainment who has worked with Midway on the home console ports of Mortal Kombat titles.
•004-400 = Displays the message: "Whatcha gun do? - E.B", a joke message from Ed Boon that possibly pokes fun at the fact of Mortal Kombat being a fighting game.

The Sega Saturn release of the game also features two exclusive developer messages:

•200-002 = Displays the message: "It should work!? - P.A.B."
•300-003 = Displays the message: "PUB! - D.K.P."
Contributed by Regen-33