Mortal Kombat was the first entry in the famous Mortal Kombat fighting game series by Midway, released in arcades in 1992. It was later picked up by Acclaim Games for the home version, then later returned to Midway. It centers on the first Mortal Kombat tournament and the ultimate defeat of the evil Shang Tsung by the monk Liu Kang.

Versions of the original Mortal Kombat game appeared on several different formats, most notably the Sega Mega Drive/Genesis and Nintendo's SNES. When the first game in the series was released for the SNES in North America, Nintendo of America had a strict "Family Friendly" policy towards the content of the games released on their systems which required the removal of graphic violence, religious imagery and themes, mentions of death, sexual themes, and other sensitive subjects. Hence, the first Mortal Kombat game on the SNES had the blood recolored gray in an attempt to pass it off as sweat, and the various Fatality moves were graphically changed to be less gruesome. The SNES version was graphically superior to the Mega Drive/Genesis port, but all violence was censored.

The game was a response by Midway to Capcom's successful Street Fighter II, which spawned a number of fighting games. However, it used a distinctly different fighting system from the Street Fighter formula, which was used in all subsequent sequels until Mortal Kombat: Deadly Alliance. The controls consisted of five buttons arranged in an "X" pattern: a high punch, a high kick, a low punch, a low kick, and a block button, as well as an eight-way joystick. If the two fighters were standing next to each other, hitting any of the attack buttons would result in a modified strike: a low punch turned into a throw, a high punch turned into a heavy elbow, headbutt, or backhand, and either kick turned into a knee strike. Crouching and hitting either punch resulted in an uppercut, which was the most damaging attack of the game. Jump kicking and crouch-kicking were executed in a similar fashion to Street Fighter, although leg sweeps and roundhouse kicks were performed by holding away while pressing the appropriate kick button.

The blocking in Mortal Kombat I by itself greatly changed the flow of fighting in comparison to contemporary games which used Street Fighter conventions. Characters do not block while retreating or crouching, but only block when the block button is pushed. Even then, characters take (reduced) damage from any hit while blocking. However, successfully blocking moves is simple – a crouching block can successfully defend against all moves, even aerial attacks such as jumpkicks – and blocking characters give very little ground when struck rather than sliding backwards. This style of blocking rewarded dodging to avoid damage but also made counterattacks much easier after a successful block, and the ultimate result was an environment which rewards a more furtive playing style than contemporary games.

Another of the game's innovations was the Fatality, a special finishing move executed against a beaten opponent to kill them in a gruesome fashion. For example, one character (Sub-Zero) would grasp a defeated opponent by the head, then rip out the head and spine while the body crumpled to the ground in a pool of blood.

Finally, Mortal Kombat also changed the way special moves were performed. Street Fighter (and many other fighting games) performed most special moves in fractions of circles (usually full, half or one-quarter) on the joystick followed by a button press (such as a quarter-circle forward, plus punch). Mortal Kombat was the first to introduce moves that did not require a button press (such as tap back, tap back, then forward), and only a few of the special moves required circular joystick movement.