In the game Mega Man X, if the player collects all items and completes Armored Armadillo's stage five times, at the end of the level above the boss door, the player will find a secret capsule in which Dr. Light (dressed as Ryu) will teach X the Hadoken. The way it is performed is the same as in the games. Unlike the usual Hadoken from the Street Fighter series, it is quite lethal, as it can kill all bosses in one hit, although X will need to be at full health in order to use it.
Also in Mega Man X4, the boss Magma Dragoon uses this as one of his attacks, the depiction of this attack is a stream of fire rather than energy; Dragoon can also fire Hadokens while crouching, similar to Sagat's Tiger Shot.
In both of the Mega Man X Game Boy Color Games Mega Man Xtreme and Mega Man Xtreme 2, X can receive both the Hadoken and Shoryuken from a hidden Dr. Light capsule in either game. To use them X needs to have his X-Buster fully charged, and holding down when firing it allows the Hadoken to be used (whereas holding up would activate the Shoryuken). Unlike their SNES counterparts, they can no longer kill bosses in one hit, though X does not need to be at full health in order to use either move.
Hideo Shimazu from Rival Schools also possess a Hadoken dubbed as "Seihaken" and his burning vigor, "Shimazu-ryuu Seihaken", resembles Ryu's Shinku Hadoken.
Batsu Ichimonji, the main protagonist of the series, also has a similar ability to the Hadoken dubbed as "Kiadan" (Guts Bullet) and his burning vigor as "Zenkai Kiadan" (Super Guts Bullet).
In Project Justice, the main antagonist, Kurow Kirishima (under his disguise as Batsu's doppelganger, "Vatsu") and Batsu's burning version also have this ability.
Wang-Tang from the Power Stone series in his Power Change form uses an ability called Dragon Fireball where he could shoot energy blasts in each palm similar to Gouken's Gohadoken. In his anime appearance, his hand gesture during the execution of the move resembles the Hadoken.
In Shanghai Kid, the first installment of Culture Brain's Hiryū no Ken series, the main protagonist Ryuhi can shoot a fireball. Since Shanghai Kid predates the original Street Fighter game by two years, it is one of the earliest (if not possibly the first), "fireball" special attack in the fighting game genre.
The Hadoken appears as a taunt attack in Valve's FPS, Team Fortress 2, and is used by the Pyro unit. If the fireball connects, it instantly kills any enemy player unfortunate enough to be hit. While it is called "Hadoken", technically it is a Shakunetsu Hadoken (as the attack is in itself a melee-range puff of flames that leaves its victims on fire).
In the Battle Arena Toshinden series, Eiji Shinjo and Kayin Amoh can shoot projectiles (named "Rekkuzan" and "Sonic Slash" respectively) which resembles a Hadoken. Eiji's older brother, Sho Shinjo, can use this ability and both Shinjo brothers have their special attack called "Enjinshouraha", also known as "Double Rekkuzan", which is two large projectiles.
In Battle Arena Toshinden 3, Leon also copied Eiji's Rekkuzan move, but as an ice-esque projectile named "Nitrogen Breath" while Abel and Veil have a projectile named "Hakidan" which resembles a small Hadoken. Their soul bombs, however, enables them to shoot more projectiles and create a massive aura blast.
Battle Arena Toshinden character Sofia also have an ability called "Thunder Ring" which resembles a lightning based Hadoken. In Battle Arena Toshinden 3, Sofia's counterpart, Zola had copied Sofia's Thunder Ring and named her own projectile as "Flash Ring".
In Double Dragon (Neo-Geo), the Lee brothers Billy and Jimmy have a projectile named "Sosyuga" and both characters will move when executing their projectile to his opponent in a close range instead of the projectile being in long range. Both of their super finishing moves creates a shadow version of Ryu's Shinku Hadoken in three hits despite the attack is in close range and deals heavy damage. In their transformed state however, they can shoot projectiles in a long range by one hand similar to Gouken's and also to shoot dragon projectiles.
In Konami's Suikoden II, the character Long Chan-Chan has a White Tiger Rune. When he activates his rune, he charges and shoots a fireball similar to a Hadoken to his opponent. Another character, Wakaba can also shoot two projectiles (with kicks) when her White Tiger Rune is activated.
In Legend of Legaia, the villain Songi has the ability called the Hyper Wave which resembles both Akuma and Ryu's Shakunetsu Hadoken. When he charges this ability, he shoots his opponent in critical damage much like how Ryu charges his Shakunetsu Hadoken in Street Fighter X Tekken.
In The Legend of Dragoon, the character Haschel has an addition move called the Flurry of Styx as the last part of the move resembles Sakura's charging Hadoken. In his Violet Dragoon Form, the last part of his Dragoon Attack resembles Ryu and Gouken's Denjin Hadoken.
Dart's father, Zieg Feld's Flame Shot magic resembles a powerful version of Ryu's Shakunetsu Hadoken.
In Nintendo's Kirby series of platform games, Kirby's Fighter ability allows him to use a fireball that resembles the Hadoken, and even wears a headband as a tribute to Ryu.
To go even further, in Kirby's Return to Dream Land, pressing down, forward, and then "1" on the Wiimote, Kirby can perform an instant fireball. This is similar to the actual move's activation.
In the Jak and Daxter series of action-adventure games, Dark Jak's "Dark Strike" move is used in a similar way to a Denjin Hadoken; Jak charges dark energy, with dark sparks being created, and mimics the hand thrust of the Hadoken fireball being released. However, the Dark Charge projectile itself is two dark-powered fireballs twirling at once.
In Final Fantasy VI (Final Fantasy III in North America), one of Sabin's Blitzes, "Aura Cannon", has the same button commands as the Hadoken, and is visually similar to the crossover variant.
In one of the Saints Row: The Third clips, called Saints Flow, Pierce uses a move similar to the Shakunetsu Hadoken at one point. There is also a taunt named "Quarter circle forward + A" in the game, and it does a stance similar to a Hadoken.
In Call of Duty: Black Ops, Takeo, the stereotypical Japanese character from the Zombies Mode, will yell "Hadoken!" at certain times in the game (usually when he gets a gun that shoots electricity, which is unavailable most of the time). In one of the maps, Kino Der Toten, it's a quote that didn't make it into the final version of that map, but it's hidden within the files on the disc. In other maps, he actually does say the quote, though very rarely.
In Scott Pilgrim vs. the World: The Game, NegaScott can perform a Shakunetsu Hadoken as one of his tech attacks. When performing the move, NegaScott's hand movements are near identical to the hand thrust used for the attack. The Hadoken ignores collision and can attack multiple enemies.
In The Simpsons Game, an enemy in the level "Enter the Cheatrix" has similarities to Ryu, and fires Hadokens at the player.
In Ragnarok Online, both male and female Monk and Champion class can unleash a move called Occult Impaction which resembles the Hadoken that deals multiple hits.
In the online game, RAN Online, the male and female Brawler job does a Rays Cyclone technique which resembles Sakura's Shinku Hadoken as well as its gesture during execution.
In the French version of Pokémon Red and Blue, the fighting game is hinted to be a Street Fighter II title, with explicit, if misspelled references to the Hadoken being used during a battle between Ryu and Ken.
In the online card game Kongai (which has art illustrated by UDON), the character Angelan Series D has a move which shares the same name.
In Episode 33 of the manga/anime series Keroro Gunso, the character Tamama uses a parody version of the Shinku Hadoken called Shinku Tamamaken; the attack looks exactly the same.
In Episode 41 of the manga/anime series Yu Yu Hakusho, the main protagonist, Yusuke Urameshi has a Spirit Wave ability similar to the Shinku Hadoken when he uses this to knock Jin in mid-air with one powerful punch, creating a powerful wave. In Episode 49, Genkai's Spirit Reflection Blast also has a resemblance of the Shinku Hadoken when she absorbs Shishiwakamaru's energy twice. She turns on her younger appearance using the Reihado-ken during the absorption in Shishiwakamaru's spirit energy to take the initial hit on her Spirit Reflection Blast on him. In another episode, Episode 51, Minorenjya's projectile is similar to Ryu's Hadoken in Street Fighter II V, but in acidic properties as everyone including the referee Juri are complaining about the disgusting smell from his projectile as Koto also remarks that this projectile can melt everyone in excruciating in pain when it was unleashed.
In Mobile Fighter G Gundam, the God Gundam (or Burning Gundam in the English version), and its pilot, Domon Kasshu, possessed a move called "Sekiha Tenkyoken", which bears a faint resemblance to the Shinku and Denjin Hadoken in pose and/or projectile; with Domon's Shuffle Alliance insignia branded in front.
In one of the episodes of Random Cartoons!, during the short "Hero Heights", Brainiac does a move similar to the Shinku Hadoken, yelling out "HADAYUKEN!".
Stand-up comedian Daniel Tosh references the Hadoken as a "finisher" in order to kill his grandmother in his stand up special, "Happy Thought's". However, he implies that it is from Mortal Kombat, another popular fighting game in which a player can finish their opponent by using a "Fatality". Tosh also yells "Hadoken" during Force Field Paul's web redemption (he says it at the 6:20 mark).
In one of the episodes of the Brazilian MTV show, Tela Class (which shows little-known movies with spoofed dubbing in Portuguese), a scene shows characters in a brawl at a casino. The brawl starts as soon as the word "Hadoken!" is shouted, though the character who says it does so while punching another one's face instead of shooting any sort of projectiles. The dialogue for the scene (seen here, starting at 4:41) is as follows:
A: If you're gonna mess with him, you're messing with me too! 'Cause I'm his protector!
B: Protector? You're an idiot, that's what you are!
A: Oh yeah? HADOKEN!!!
In The Amazing World Of Gumball, during a fighting scene that parodies the fighting game genre, Darwin and Gumball use the Hadoken, and their attacks resemble Ken and Ryu's, respectively. Darwin also says "Big Head!" as he uses the attack.
In the webcomic 8-bit Theater, created by Brian Clevinger, the character Black Mage uses the Hadoken to deal massive amounts of damage to different enemies. The move looks like a steady stream, similar to its appearance in the Vs. series, and is a play on how the original Final Fantasy for the NES saw Mage characters cast their spells in a fashion similar to the Hadoken.
At one point, Fighter tries to perform the Hadoken but performs the Shoryuken instead, saying he "messed up the buttons".
Several "variants" of the move appear:
Black Mage performs a "Fighterdoken" by throwing Fighter at enemies.
Later, Fighter uses the move against Drizz'l, calling "Me-doken!"
After the party changes classes, Red Mage mimcs the attack, yelling "HADOYASTOPTHIS!?"