Mortal Kombat is a fighting game in which players battle opponents in 1v1 matches. The fighter that drains the opponent's health bar first wins the round, and the first to win two rounds wins the match. Each round is timed; if both fighters have health remaining when time runs out, the one with more health wins. Two players can start a game together, or a second player can join in during a single player's game to fight against them. If a game was in progress at the time, the winner continues it alone; if not, the winner begins a new game.
Mortal Kombat uses an 8-directional joystick and 5 buttons, including 2 punch and 2 kick buttons, each further differentiated between high and low. Attacks can vary depending on the player's distance from the opponent. All player characters have a shared set of attacks performed by holding the joystick in various directions, such as a leg sweep and an uppercut. The latter attack knocks the enemy high into the air and causes much damage. Most special moves were performed by tapping the joystick, sometimes ending with a button press. Unlike previous one-on-one fighting games, few moves require circular joystick movement. The game's blocking system also distinguished itself from other fighting games, as characters take a small amount of damage from regular moves while blocking. However, the dedicated block button allows users to defend against attacks without retreating. Blocking characters lose very little ground when struck, thus making counterattacks much easier after a successful block.
Mortal Kombat further introduced the concept of "juggling", knocking an opponent into the air and following up with a combination of attacks while the enemy is still airborne and defenseless. The idea became so popular that it spread to many other games. Another of the game's innovations was the Fatality, a finishing move performed against a defeated opponent to execute them in a gruesome fashion.[6]
In the single-player game, the player faces each of the 7 playable characters in a series of 1v1 matches against computer-controlled opponents, ending in a "Mirror Match" against a duplicate of the player's chosen character. The player must then fight in 3 endurance matches, each involving 2 other playable characters. When the player defeats the first opponent, the second one enters the arena, and the timer resets; however, the player's health meter does not regenerate. After the third endurance match, the player fights the sub-boss Goro, followed by a final match against Shang Tsung.
Between certain levels, players can compete in a minigame called "Test Your Might" for bonus points, breaking blocks of various materials by filling a meter past a certain point through rapid button presses. The first material the player must break is wood, followed by stone, steel, ruby, and finally diamond, with each successive material requiring more of the meter to be filled up and thus awarding more points.