Spoilers Off for MK1, MK2, MK3 and MKM:SZ. You Have Been Warned.

The One With… low-poly 3D Fatalities.

After Mortal Kombat 3 and Mortal Kombat Mythologies: Sub-Zero, Midway decided it would venture into 3D — which gave rise to Mortal Kombat 4, released for the arcades in 1997.

Thousands of years ago, Raiden waged war against former Elder God Shinnok; this war ended an entire civilization, and Shinnok was later condemned to the Netherrealm. Bi-Han, the original Sub-Zero was deceived to free him, and years later, Shinnok allies himself with the villainous Quan Chi. With the help of Edenian traitor Tanya, the evil duo ascended to the Heavens and killed most of the Elder Gods. Raiden and the Wind God Fujin escaped, then gathered Raiden's most trustworthy allies in order to defeat Shinnok and his allies.

Developed on Midway's newly built ZEUS arcade board, which boasted a capability of pushing 1.2 million polygons on-screen (for reference, the PS1 could only render up to 360,000 flat polygons), MK4 swapped the use of digitized live-action actors and 2D backgrounds of the previous entries in favor of employing a fully polygonal 3D world (note that Midway made a prior 3D fighting game War Gods, which was seen as something of a precursor to this game, an attempt to make a "3D Mortal Kombat" before the real deal, the actual development team between both games were unrelated and there's no crossover between staff members). The game's fighting system was also revamped to allow for the kombatants to switch between unarmed kombat and the wielding of a blunt weapon, which could also be disarmed from an opponent and used by oneself.

Prior to its wide release, MK4 underwent a nationwide location test period promoted as the "Mortal Kombat 4 Road Tour", in which Midway brought over various prototype cabinets to select arcades throughout 29 cities within the US and have players test the game out first. Notably MK4 underwent two revisions during this period, with the initial version of the game having a slightly different roster from the later builds (notably Noob Saibot was present as part of the initial playable roster, although he was later replaced by newcomer Reiko).

MK4 would later be ported to the PlayStation, Nintendo 64 and PC CD-ROM in 1998, followed by an updated version with the release of Mortal Kombat Gold for the Sega Dreamcast in 1999, which brought back six veteran kombatants.

It would be the last game in the series to get an arcade debut, as all the future fighting game entries from Mortal Kombat: Deadly Alliance and onward would be developed strictly as home console games.

See also:

• The franchise's Developers' Foresight page
• The franchise's Shout Out page
• The franchise's Stage Fatality page

The game has the following trope examples:

• Acid Attack: Reptile retains his signature acid spit from previous game, but now the acid is affected by gravity; this isn't a problem, because the range of the spit is still wide.
• Adaptation Expansion: Storywise, the updated re-release Mortal Kombat Gold takes the base roster and adds returning faces that were omitted in the base version of 4. This leads to an expansion of the individual characters' stories and profiles to account for what the expanded roster were doing during Mortal Kombat 4's base storyline, like Kitana, Cyrax, and Mileena.
• Ambidextrous Sprite: Surprisingly for a 3D game with models, they do this at changing sides.
• Anti-Frustration Features: The game introduces a Maximum Damage cap regarding combos. In previous games, some characters (like with Kitana and Scorpion in Mortal Kombat II or with Sub-Zero and Noob Saibot in Ultimate Mortal Kombat 3) were capable of 100% combos, which would effectively guarantee a victory if pulled off, and some of them (especially Noob Saibot's) were rather easy to perform with practice. Mortal Kombat 4 instead forcibly makes both players backflip away from each other if 40% of an opponent's health is drained in a single combo (though it's possible to exceed it if the final blow deals a significant amount of damage).
• Battle Boomerang: Tanya uses one as her weapon during fights. It only returns to her when thrown if it connects to the opponent.
• Big Head Mode: This is one of the Kombat Kodes. For some reason, it also affects the skeleton hands that Shinnok summons in his Fatalities. In one of them, they get too big to fit through the portal.
• Big "NEVER!": Four of the endings (actually six, but Jarek's is used in three different endings which start in the same situation^note Sonya's, his and Jax's, also Kitana's in Gold).
• Bond Villain Stupidity: In both Scorpion and Sub-Zero's endings, Quan Chi just cannot resist gloating with an enemy only knocked out nearby and it always goes badly for him. In Sub-Zero's, the sorceror says aloud that he never had any intent of fulfilling his ending of the deal with Scorpion, causing the ninja spectre to kill him. In Scorpion's, Quan Chi outright tells Scorpion that it was he, and not Sub-Zero who killed Hanzo's family and clan and while he quickly sends Scorpion back to the Netherrealm, Hanzo manages to drag Quan Chi with him.
• Border-Occupying Decorations: Playing the Game Boy release on the Super Game Boy puts four skulls on the sides and the game's logo at the top.
• Camera Abuse: Several Fatalities hurled the remains of the defeated player at the camera, bouncing off it and splattering the screen in blood.
• Cap: Introduced to prevent players from being locked in endless combos. It could be turned off in the home versions though.
• Captain Obvious: Baraka's ending is rife with it.
  Quan Chi: The Elder Gods are dead, Raiden is dead, and thanks to you, Shinnok is dead.
  Baraka: Everyone is dead!
  Quan Chi: Yes, everyone in this forsaken realm... is DEAD!!!
  Baraka: How do you rule a realm with no one in it!?
• Chuck Cunningham Syndrome: Kitana's only appearance in MK4 is as a barely visible figure in Liu Kang's ending, while Jade and Sindel don't appear in this game at all^note Sindel is briefly mentioned in Tanya's bio, and both Kitana and Sindel appear in the game's official comic book detailing how Shinnok successfully invaded Edenia, even though it's set in their homeworld of Edenia (Gold somewhat rectified this by including Kitana and Mileena as playable characters). Also, Noob Saibot is only a secret character, despite his presence in UMK3 foreshadowing Shinnok's return in this game.
• Continue Countdown: A particular creepy one. Your chosen character will keeps flailing and falling into a deep well as the countdown keeps running. If the player does not wish to continue, the character eventually reaches the bottom of the well and is promptly impaled on some spikes.
• Darker and Edgier: Takes itself much more seriously than Mortal Kombat 3, despite that game's ostensibly darker plotline. There's no Friendships, Babalities, Animalities, etc, and the Fatalities are generally much less goofy. Still has a fair share of Black Comedy in many of the Fatalities, and the endings are unintentionally hilarious, but for the most part it's a lot more tonally consistent.
• Did You Just Scam Cthulhu?: As shown in his ending, Quan Chi gave Shinnok a worthless duplicate of his magical amulet while keeping the original for himself and using it to supplant Shinnok immediately after. He even fooled Raiden with it. Quan Chi managed to hold on to said real amulet from Deadly Alliance all the way up to Armageddon too so that was some impressive scamming.
  Quan Chi: I am in possession of your once sacred amulet! Years ago I delivered to you an exact duplicate, while I retained the original. I even fooled Raiden!
• Ditto Fighter: Shinnok is a Tsungxpert variety, except he doesn't transform like ol' Shang.
• Dragged Off to Hell: Done in Scorpion's ending. Quan Chi, having admitted to murdering Scorpion's family and ninja clan, magically sends Scorpion back to the Netherrealm...only for Scorpion to grab and take Quan Chi to the depths with him, much to Quan's horror.
• Dramatic Spine Injury: Each character has a move called "Bone Breaker", with four of them attacking the opponent's back:
  • Kai picks up the opponent and slams their back down on his knee.
  • Sonya jumps into a handstand on the opponent's shoulders and twists their torso 180°.
  • Liu Kang turns the opponent around and kicks the lower portion of their back, bending their body in an arc.
  • Goro holds the opponent over his head with his upper arms and uses the other two to punch the opponent's spine, visibly bending their torso.
• Dumbass Has a Point: It's Baraka of all people who thinks to ask what the point of conquering a realm is if you're just going to kill everyone in it.
• Evil All Along: Tanya pretends to be on Liu Kang's side, but is actually working for Shinnok.
• Game-Breaking Bug: The arcade version suffered from two deadly bugs:
  • In the very first arcade release, it is possible to bring a match to an abrupt standstill if one fighter used a special ability to lift an opponent to the top of the screen, as this would put him or her too high out of reach for either to attack each other. The only way a match affected by this bug would end is via a time-over, so this bug basically softlocks the game if no time limit was imposed.
  • Performing Reptile's Acid Spit Fatality against Scorpion would crash the game on Revision 3.0.
• Guilt-Based Gaming: The continue screen has your character falling down a pit. In the arcade version, if you don't insert quarters to continue, they get impaled by spikes at the bottom of the pit; five seconds of this music are more than enough to make you pop in another quarter. In the home console versions, the countdown will be based on how many continues you have left (usually three at most, but a secret menu can raise the number to up to nine), motivating you to press Start ASAP to save your character if you have too few continues (or even just one) left.
• Home Stage: In addition to bringing back Goro's Lair, the game also introduces Reptile's Lair.
• Ignored Epiphany: Scorpion discovers that the elder Sub-Zero (whom he killed in the first game) was never involved in his family's deaths, that he had been framed, and that Scorpion's thirst for vengeance against him was uncalled for. That would mean Scorpion would not make any more poor decisions based on revenge, right? No, as Scorpion instead transfers his hate towards the actual culprit: Quan Chi. Scorpion's vengance would make him spend most of the following game torturing Quan Chi until he escaped from the Netherrealm and formed the deadly alliance with Shang Tsung, basically kickstarting the events of that game.
• Kukris are Kool: Kai uses the "Gurkha Knife" or kukri as his weapon of choice.
• Laser Blade: In Gold, Cyrax has the "Sabre of Light". Later on it's given the name of "Pulse Blade" in Mortal Kombat: Deadly Alliance.
• Love Ruins the Realm: This is the reason why Liu Kang refuses to become Edenia's king, alongside Kitana, in his ending.
• Mini-Boss: Goro serves this role in the home console versions of the game, right before Shinnok who's the Final Boss. In the arcade version, it was Quan Chi. It made sense from a storyline perspective, but he was a selectable character from the very start already.
• Moveset Clone: This is actually the first game in the series to defy this trope, due to fan backlash regarding clones in the previous games. The only straight example is Noob Saibot, who still borrows some moves and Fatalities from various characters (most notably from Reiko).
• Nostalgia Level: The Living Forest and Goro's Lair return, complete with rearrangements of the old BGM. Also returning are the Shaolin Temple and Wind World. The Gold release adds the Church, Soul Chamber, and a combination of Scorpion's Lair and Kahn's Kave.
• Player Death Is Dramatic: If you lose, your player character is dropped into a well and they tumble to their doom. If you don't have enough credits to continue, they fall to the bottom and get Impaled with Extreme Prejudice on a bloody spiked floor. Game Over.
• Pre-Mortem One-Liner: Delivered to Jarek in Jax's ending, as Jax is holding Jarek by the neck over a cliff.
  Jarek: "You have to uphold the law! You have to arrest me! Wait! Wait! This is brutality! You can't do it!"
  Jax: "Wrong Jarek, this is not a Brutality, this is a Fatality." (The "Finish Him" music plays as Jax drops him.)
• Produce Pelting: A booing crowd throws fruit, bottles, and cans at Johnny Cage during his ending.
• Revisiting the Roots: MK4 brought back most of the cast from the first two games (until some were reskinned near the end as "new" characters), the mythological Asian look after MK3 focused on Earthrealm locations and Western-oriented characters, two Nostalgia Level selections, and a bulk of the Fatalities were 3D updates of classic Fatalities from the first two games.
• Satanic Archetype: The fallen Elder God Shinnok, who in the backstory attempted to overthrow his fellow Elder Gods and conquer Earthrealm, but was defeated and banished to the Netherrealm (which happens to be a fiery wasteland where evil beings hang around, blatantly Hell). At some point, with the aid of Quan Chi, he overthrew and usurped the title of the Netherrealm's ruler from Lucifer.
• Secret Character: The original arcade version has a rare player-exclusive version in Meat, who uses the skinned corpse model utilized in a couple of Fatalities but uses other characters' moves instead and can be unlocked. The console versions add Goro and Noob Saibot, both of whom are playable by selecting Shinnok or Reiko respectively while using the Hidden option. As a throwback to his role as one in the first game, Reptile became this in the Game Boy Color version. MK Gold added Sektor to the mix by doing the same with Cyrax.
• Set Swords to "Stun": Characters have weapons now, mostly daggers and swords. Swords are inflicting much less damage than one would expect: for non-human characters, this is somewhat justified, but Sonya for example is a regular human, so a full contact swing of a sword should do much heavier damage to her body than it does in the game - if not outright incapacitate/kill her. Also, the bone breaker moves have no effect on the characters apart from doing some damage, as the fighters can use their (supposedly) broken limbs normally. The most extreme example is Liu Kang's, as his bonebreaker has him breaking the opponent's spine... of course the other fighter jumps back into the action after a few recovery frames.
• Sinister Scythe: Noob Saibot uses a scythe as his weapon.
• Skull for a Head: Noob Saibot has an alternate costume that gives him a skull helmet (and another alternate costume that gives him a hood covering his head and obscuring his face). Along with his shadow powers and Sinister Scythe, it makes him look a lot like The Grim Reaper.
• Un-Evil Laugh: Jarek has an odd, muffled laugh in his and Jax's endings.
• Updated Re-release: MK Gold for the Sega Dreamcast, which added several characters that weren't present in the original version.
• Use Their Own Weapon Against Them: If a character drops a weapon during a match, their opponent can pick it up and use it against them. Quan-Chi additionally has a special move that allows him to steal an opponent's weapon straight out of their hands.
• We Can Rule Together: Heroic example: In Liu Kang's ending, Kitana manifests in the Shaolin Temple to thank Liu for his help in defeating Shinnok and offers him the chance to rule Edenia at her side. Liu Kang, being the Mortal Kombat Champion, politely declines.
• What Does She See in Him?: In Tanya's ending. When Liu Kang follows her into a trap where Shinnok and Quan Chi are waiting for him, she wonders what Kitana saw in him.
• Wind Is Green: Fujin the god of wind has a green theme, with green pants, grey hair with a green tint, green energy attacks and green bolts shot from his crossbow.
• You Will Be Spared: In Quan Chi's ending, this is his "reward" for helping Shinnok. He does not take it well and challenges the fallen elder god. He actually WINS.
  Shinnok: As payment for your loyal services, Quan Chi, I grant you the gift of your existence.
  Quan Chi: My existence?!
  Shinnok: Understand, sorcerer, I consume all energies, including the life forces of all that live. But I shall spare you.
• Your Reward Is Your Life: In Quan Chi's ending, he meets his deity and master, fallen god Shinnok, who congratulates Quan Chi and rewards the sorcerer with "his existence". Quan Chi questions the meaning of Shinnok's words, and the deity explains he consumes the life force of all, but decided to spare Quan Chi.