Mortal Kombat 9 could as well be considered a celebration of the best of the franchise, given the tons of nods towards the series mythos, both the original continuity and the extraofficial material.
Character moves and poses
- Johnny Cage's autographed headshot friendship from 2 and the movie is also referenced in his Babality in this game, where it's replaced by a doodle version.
- Kitana's X-Ray makes heavy use of the teleport spin shown in the DC crossover.
- Liu Kang's X-Ray Move starts a butterfly kick followed by an uppercut to the chin and then a high kick to the chin. The first two moves are a homage to his Fatality in the first game, the only non-fatal Fatality in the series.
- When he wins a round, he makes a gesture of respect and disappears in fire. That's the same thing he does in his 3 fatality, right before the arcade console falls on his opponent's head.
- Mileena's X-Ray move is essentially her "Rapid Stab" fatality from 2.
- Noob Saibot's fighting stance is the same as Sub-Zero's in the first two games and Mythologies, referencing his status as the original Sub-Zero.
- In the intro movie of Deception, Quan Chi opens a portal to escape when he realizes that Raiden's going to try and kamikaze Onaga. He opens the same portal when he tags out during a tag match during 9.
- Shang Tsung's opening quote in 9 is "Your Soul Is Mine!", his catch phrase from the first film.
- Sonya Blade's Kiss of Death special is a kiss made with chemical-dust, the same trick she uses in Mortal Kombat: Annihilation.
- Sub-Zero tags out using the Tombstone teleport from MK vs. DC.
- Goro has his "Limb Rip" fatality from Deception, rechristened "Torn Apart".
- Jade has her pole impale fatality from 3.
- Jax starts his "Three Points!" fatality with Superman's Ground Pound from MK vs. DCU. The entirety of the Fatality is also similar to Shao Kahn's "Fore!" fatality from Deception, except that he uses his hands and feet instead of a weapon.
- He also starts his "Smash and Grab" fatality with his "Head Clap" fatality from 2 and 4.
- Johnny Cage combines his headshot uppercut from 1 & 2 and later his Torso Rip from 2 in his "Heads Up!" fatality.
- Kabal has his "Hook Up" fatality from Deception, only this time he cuts his opponent vertically instead of horizontally.
- Kano has his Heart Rip fatality from 1 as the first part of his "Eat Your Heart Out!" fatality.
- Kung Lao's "Razor's Edge" fatality is taken from Shaolin Monks.
- He combines his "Hat Decapitation" from 2 with his "Body Slice" also from 2 in his "Hat Trick" fatality.
- Liu Kang's "The Spirit Within" fatality is his "Dragon's Bite" fataity from 2 and 4.
- Mileena ends her "Be Mine" fatality with her "Ferocious Bite" from Deception. Her "Rip Off" Fatality copies one of Kira's Fatalities from the same game, using her Sai in place of Kira's Dragon Teeth (and the name itself could be interpreted as a Pun as a result).
- Nightwolf ends his "Ascension" fatality with his "Spiritual Teleportation" fatality from 3.
- Quan Chi has his "Beatdown" fatality from 4. It starts with Havik's "Batter Up!" fatality from Deception.
- Reptile has his "Yummy!" head eating fatality from 2 in his Klassic costume.
- His "Acid Yak" fatality starts in the same way he would kill Liu Kang in his stage in Shaolin Monks.
- Scorpion has his "Toasty!" fatality from 1 and 2 in his Klassic costume.
- His "Nether-Gates" fatality is a rehash of his "Lava Pool" fatality from MK vs. DC.
- His "Split Decision" fatality starts with the "Spear Slice" fatality from 2. (only this time done with a sword)
- Shang Tsung inherits The Joker's fatality from MK vs. DCU, called "Bang! Bang!". The only differences are that he turns into a generic Monster Clown and the results are far more gruesome. He even strikes exactly the same pose the Joker did after the kill.
- His "Identity Theft" fatality is Liu Kang's "Soul Invasion" fatality from Deception.
- Shao Kahn's "Home Run" fatality is taken from Deception.
- Sheeva does a variation of her Skin Rip fatality from 3.
- Sonya has her "Scissor Split" fatality from 4.
- Stryker does his Taser fatality from 3, but this time close to his enemy, before headshotting him, in his "Time Served" fatality.
- He also has a variation of his "Explosives" fatality from 3 as "Have a Blast".
- Sub Zero has his "Spine Rip" fatality from 1 in his Klassic costume.
- His "Spinal Smash" fatality is similar to his "Freeze and Throw" fatality from Deception.
- His "Have An Ice Day" fatality starts in the same way as his "Below Freezing" fatality from Deception, except that he doesn't destroy the lower part.
- Ermac: Comes from Deception/Armageddon era.
- Mileena: Comes from her alt in Deception.
- Shang Tsung: Comes from MK vs. DC.
- Stryker: A mix of his old 3 look, plus stuff from his Defenders of the Realm appearance.
- Rain: Comes from Armageddon.
- Cyber Sub-Zero: The mask he wears is based on the one that Smoke wore in Deception and Armageddon.
- Main Alternate:
- Raiden: Evil!Raiden costume from Deception and Armageddon.
- Shang Tsung: MK1 boss costume; his older self.
- Jade: Comes from Deception/Armageddon era.
- Other Alternates:
- Noob Saibot's Player 2 coloration for his MK2 costume turns his shade into Smoke, referencing their team-up in Deception.
- In the cartoon adaptation, Mortal Kombat: Defenders of the Realm, Cyrax and Sektor were respectively shown to be Asian and Black before automation. The showing of Cyrax and Sektor's human forms reveal that the reverse actually applies within canon.
- Sub-Zero's unmasked MK3 costume also more resembles the outfit he wore in a flashback episode of Defenders of the Realm.
- The Courtyard music has been arranged into a hip-hop rendition for the Street stage in 3.
- The Subway stage fatality is a Call-Back to MK3 and its variants, where the subway stage and its fatality made their debut, only now it's much gorier.
- The theme was also remixed for this game.
- The Dead Pool retains its Stage Fatality from 2.
- The Pit in both variants keep their Stage Fatality from 1.
- The Living Forest allows the players to feed their opponents to the titular trees, like in Shaolin Monks.
- The cutscene-only Wu Shi Academy is kept intact from it's selectable appearance from MK vs. DC.
Arcade ladder endings
- Ermac's Arcade Ladder ending reveals that one of the souls within his body is that of the late King Jerrod of Edenia (i.e. Sindel's husband and Kitana's father), who takes control of Ermac's body and returns to rule and protect Edenia alongside his family. This is a clever and very, very subtle nod to him being often paired up with Sindel in Ultimate Mortal Kombat 3 and Mortal Kombat Trilogy during Endurance matches.
- The narration in Sub-Zero's Arcade Ladder ending refers to Subby & Scorpion as the "Deadly Alliance".
- The way Shao Kahn explodes at the end of each Arcade Ladder is reminiscent of the way Dark Kahn explodes in MK vs. DCU.
- The structure of the Story Mode itself is taken from the DC crossover.
- Raiden mentions Bi-Han!Sub-Zero's intervention against Shinnok's forces after he's cremated by Scorpion and all that is left of him is his skull and spine in an ironic reference to his own fatality in the first game.
- Chapter 2, Sonya Blade's, involves her fighting against Kitana and Jade in a two-on-one match. This includes a multitude of Easter eggs that one would likely not realize at first. Chapters 1-5 covered the events of the first game even though Kitana didn't debut until Mortal Kombat II, however she was originally conceived as a prototype NPC character named "Kitsune" who was to be the daughter of Shang Tsung (then named "Shang Lao"). Thus her appearance in the early part of the story mode is both a Development Gag and Mythology Gag in reference to her role in the 1995 Mortal Kombat movie. In regard to Jade, the creators of the aforementioned film had planned to include a fight between Sonya and Jade which was ultimately never shot, though it is included in the novelization of the movie.
- Smoke's chapter has him spying on Shang Tsung and Kano behind a tree in the Living Forest, much like he did on the player back in MK2.
- During Kuai-Liang!Sub-Zero's chapter, he has a conversation that is very similar to his lines in Mortal Kombat: Annihilation.
- Kitana's affections towards Liu Kang were also ported over from their relationship in the movies.
- Jade is revealed to be spying on Kitana in the Living Forest during Kitana's chapter, much like in MK2.
- Kung Lao being disguised as a Guard and revealing himself in Scorpion's chapter is a nod to the intro of Shaolin Monks, where he did the same.
Kung Lao: I hope your girlfriend is worth Lord Raiden's anger, Liu Kang.
Liu Kang: Notice that I am ignoring you.
- During the story mode, Kung Lao faces off against the tandem of Quan Chi & Shang Tsung. Quan Chi even remarks that Kung Lao doesn't stand a chance "against this Deadly Alliance".
- In Chapter 15 (which takes place during the MK3 portion of the story line), Nightwolf fights against and defeats Quan Chi. In Mortal Kombat: Defenders of the Realm (which is set during the events of the third game), Nightwolf was the lone member of the Defenders of Earthrealm who could overcome and break the spell cast by Quan Chi.
- Kabal and Stryker being partners in the police may reference a line by Rain in Mortal Kombat: Annihilation where he claims to have killed them both in battle.
- Several characters refer to the Bad Future where Shao Kahn wins as "Armageddon". Sure enough, the plot of the game hinges upon you being able to avert the events of the game of that same name.
Challenge Tower & Bonus CT
- Mortal Kombat: Armageddon
- Raiden fighting against Taven, in order to prevent him from stopping the bad guys led by Quan Chi to reach Argus' Pyramid.
- Raiden making a deal with the aforementioned bad guys.
- Mortal Kombat: Deception
- Raiden, now a bad guy, reanimating Liu Kang's corpse.
- Raiden, Shang Tsung and Quan Chi trying to stop Onaga, a reference to the intro.
- Also from the same intro, Raiden battling Shang Tsung and Quan Chi, the Deadly Alliance from the previous game.
- Mortal Kombat: Deadly Alliance
- Raiden telling the Earthrealm warriors about the Deadly Alliance.
- Raiden receiving the request of Kuai Liang, the new Lin Kuei leader, to join Earthrealm's cause (Sub-Zero's DA ending).
- Near a portal in the Special Forces base.
- Raiden finding the deceased Liu Kang's corpse.
- Mortal Kombat 4
- Mortal Kombat 3
- Liu Kang's attempt to stop Shao Kahn's invasion.
- The Tarkatans wreaking havoc in Earthrealm.
- Johnny Cage being impaled by Motaro.
- Raiden discussing with Nightwolf about Sindel's resurrection.
- Jax getting his cybernetic arms implanted.
- Smoke's capture and automation.
- The Soulnado.
- Mortal Kombat II
- Liu Kang finishing Shao Kahn.
- Kano and Sonya being captured in the Collisseum.
- Sonya battling the Tarkatans, being outnumbered and captured.
- Mortal Kombat
- Liu Kang defeating Shang Tsung.
- The birth of Noob Saibot as a result of Scorpion killing Sub-Zero.
- Reptile attacking Johnny Cage.