In some official Street Fighter II artwork as well as Street Fighter IV, Ryu's belt has four kanji emblazoned upon it: kaze (wind), hayashi (woods), hi (fire) and yama (mountain); these four kanji make up the furinkazan. The four words are based on chapter seven of Sun Tzu's The Art of War, which dictates how one should conduct battle.
Eagle, while starting out as Capcom's version of the bodyguard in Bruce Lee's movie Fist of Fury, was slowly retconned from Capcom vs. SNK 2 onwards into an Expy of Freddie Mercury; from being the first openly gay character of the franchise to the uttering of phrases like "The show must go on" and "No time for losers".
One of Blanka's alternate costumes in Street Super Fighter IV looks exactly like Lobo.
His new alternate costume is a tribute to Dan, due to their friendship.
Guile's appearance and military involvement (maybe not so much which team) is also inspired by Rudolf Von Stroheim. They're both hi-rank soldiers, they're both from an army with a bad name, but they're both good guys. It's ironic, however, that Rudolf Von Stroheim is a NAZI, the furthest thing from an all-American.
In Street Fighter II, there was an infamous glitch performable by Guile known as "Handcuff", that could keep an opponent freezed in a "hurt" sprite indefinitely, that would be later acknowledged by Capcom in one of his winning quotes in Alpha 3.
"No handcuffs!? Fighting isn't what it used to be!"
His alternate costume from IV is Charlie.
While Charlie is Guile's Expy moveset-wise, the in-universe story is that Charlie taught him those moves and was ultimately more proficient with them (such as performing his Sonic Booms with one hand or--in the case of his Sonic Break super--with his leg and performing the Somersault Shell/Flash Kick backwards) than Guile, whose skills were hampered by his lack of emotional control at the time. As a Call Back to all of this, Flash Explosion (Guile's first Ultra in IV) has Guile performing a Charlie-style Flash Kick as his second move, showing that Guile has finally been able to fully grasp his late best friend's teachings.
Zangief's appearance is based on legendary WWF/WWE wrestler Boris Zhukov, as seen here. Zangief's definitely a Face, though.
His Siberian Blizzard ultra combo in Super Street Fighter IV is the Kinniku Driver. The only difference is the lock up and the landing.
His purchasable costume in Street Fighter IV is the same attire worn by Mike Haggar.
Balrog's original name in the Japanese release was "Mike Bison", as a reference to... guess who.
One of his quotes from Alpha 3 is an obvious reference to the infamous boxing match between Mike Tyson and Evander Holyfield, in which Tyson bit one of the opponent's ears off:
"If you fight like that again, I'll bite you ear off!"
He was thought to be the successor of Mike from the first Street Fighter (in the Japanese version, the initial in his name actually stood for Mike), if not the same character. Capcom insists they're both two different characters though, but has yet to prove this by including Mike in a 2nd game appearance.
In Super Street Fighter IV, he has an alternate costume based on Apollo Creed.
There's also Fei Long. He makes a reference to Bruce Lee and his son in his original English ending in SSFII
One of his alternate outfits in IV is taken from Enter the Dragon. His second alt in Super IV is Kato. A popular PC mod for Fei Long adds in the yellow tracksuit from Game of Death.
M. Bison/Vega's outfit and physical appearance are based on Shin and Raoh, respectively. His attitude and fighting style has a little bit of both.
Since being voiced by Norio Wakamoto, he also shares the voice with Shuren, as well.
Another source of inspiration for Bison can be found in Washizaki, a villain from the infamous Gorn manga, Riki Oh. Washizaki himself is an expy of the Big Bad Yasunori Kato from Doomed Megalopolis/Teito Monogatari.
In IV, one of his green colors makes him resemble Brocken Jr. from Kinnikuman.
His DLC outfit in Super Street Fighter IV makes him look like Sigma.
SFII has a "trash the bad guy's car" mini-game, similar to the one in Final Fight. In fact, in Super Street Fighter IV, if you win the car smash bonus stage with Guy or Cody, the SAME GUY from Final Fight appears, and says "Oh My Car!" just like in Final Fight!
Dee Jay (a kickboxer and musician) is likely based on Billy Blanks (a famous kickboxer and actor).
One of his victory quotes from SSFIV is a reference to Cool Runnings.
"Feel the rhythm! Feel the rhyme! Get on up, it's Dee Jay time!"
Cammy's alternate outfit for SSFIV is directly inspired by Alita's clothes in Last Order.
Chun-Li has her Alpha costume in Super IV.
In Street Fighter III, one of Chun-Li's win quote is "Hey leave me alone. I'm a fighter, not a news reporter". Ironically in Street Fighter: The Movie, Chun-Li was portrayed as a news reporter and that quote is likely a reference to that.
His Final Destruction Super in Alpha 3 is an extended reference to the arcade version of Final Fight, where, playing as Cody, you could hit the opponent twice, turn around, quickly turn back, and repeat, for an infinite combo. The X-Ism version of this move simply turns his punches into his basic combo from FF and his jumping kick into the Crack Kick.
This victory quote is a Title Drop reference towards his origins:
"With so much riding on my fists, this will not be my final fight!"
In the intro for Super IV and in some artwork from the time of Alpha 3, Cody shames through a wall with 'Street Fighter' written in graffiti, reminiscent of the intros to both the first Final Fight and the first Street Fighter.
In SSFIV, one of his Ultra Combos has him break out the pipe, one of the weapons from Final Fight.
There's also his victory quote in his rival match with Guy:
"Guess I'm better at street fighting."
And, in being updated for Alpha 3, he was given Joe's "rolling sobat" from the original Street Fighter.
Sakura states that she enjoys street fighting as opposed to "sparring with Rival Schools". She was a playable character in the first Rival Schools.
She uses the gym uniform she wears in the Sakura Ganbaru spin-off manga as one of her costumes.
Dan is a Take That to Art of Fighting, especially Yuri Sakazaki (some of his taunts), Ryo Sakazaki (outfit, father, fighting style), and Robert Garcia (appearance). His father's appearance was also based on Mr. Karate himself. And one of his win quotes from Alpha 3 is a reference to these origins:
Due to him being based off of Robert Garcia, he ends up looking like Steven Seagal, something that is made even more noticeable with his appearance in IV. Behold!
His Hisshou Buraiken super has a name quite similar to that of Hissatsu Buraiken, the Japanese name for the Beat'Em Up known as Avengers in America.
His Haoh Gadoken Ultra shares the distinct appearance of the Haoh Sho Koh Ken performed by the previously mentioned Sakazaki family.
One of his alternate costumes is a tribute to Blanka, due to their friendship. He has another where he's dressed as his father Go, complete with a Mr. Karate-style tengu mask to mimic the old man's long nose.
Rose's appearance and fighting style is a clear reference to her inspiration, LisaLisa Joestar of Jo Jos Bizarre Adventure.
Her downloadable alternate outfit in Street Fighter IV is remarkably similar to Moriah the Thief's outfit.
Her Soul Satellite Ultra is very similar to Strider Hiryu's Oroboros super in the Marvel vs. titles, earning it the Fan Nickname of Souloboros. To a lesser degree, it also resembles Athena's Shining Crystal Bit DM. The attack's activation includes a chime reminiscent of Power Stone.
In Alpha 3, Guy cranks a corny joke about how he has his opponent "on a chain". This not only references how he was one of two characters to retain the ability to perform chain combos in the Alpha series (the other was Gen), but his nigh-dominant status in the original Alpha.
His new Ultra Combo in IV ends with the an Izuna Drop (a technique created in a manga called Ninpu Kamui Gaiden and used by several ninja in fiction such as Strider Hiryu and Ryu Hayabusa), its buildup and execution remarkably similar to the Front/Primary Lotus. The name of the Ultra is the Bushin Goraisenpuujin.
He also gets three references to Final Fight in the Alpha series:
His Bushin Gokusaken chain combo is his basic combo.
His usual intro pose involves him destroying Final Fight oildrums several times. (His regular intro, SFA manga, SFA3 intro with Cody, Super SFIV intro, etc.)
His intro against Cody in Alpha 3 has Guy performing a Bushin Tatsumaki Senpuukyaku, losing some health, and then regaining it by picking up some food. Said move was a Desperation Attack that sacrificed some of Guy's vitality. (Health could be recovered by eating food pickups located inside said barrels.)
Alpha has the Variable Battle mode from Alpha 3 Max for PSP, which is clearly based on the Marvel vs. Capcom games, with the exception of being 2-on-1 battles instead of 2-on-2 and the inability of doing double supers. Here's an example. This was also present in the Dreamcast version.
He's also a giant reference to boxing anime in general; in specific, he's got Ippo Makunouchi's Dempsey Roll and his Rolling Thunder animation in IV combines the Dempsey Roll with Sendo Takeshi's Smash. His Machine Gun Blow is very similar to the Flicker Jab move used by another Ippo character, Ryo Mashiba. He also displays his own take on Date Eiji's (yet another Ippo character) Corkscrew with both his Corkscrew Blow in III and his Corkscrew Cross in IV. Another famous boxing move in Dudley's arsenal is Joe Yabuki's Cross Counter (complete with Joe's signature drooping-arms pose).
On his gloves for the 10th color scheme of Dudley's alternate costume, the phrase "Flash" (as in Flash Gordon) can be clearly seen.
Speaking of which, his new alternate costume in Super Street Fighter IV is a cross between the famous outfit that Freddie Mercury wore at Wembley Stadium in 1986 and something that came from Sgt. Pepper's Lonely Hearts Club Band. The 10th color scheme for his alternate costume removes the jacket altogether, something which Mercury did in the Wembley concert.
Remy's ending in 3rd Strike (deceased sister being encased in ice in the depths of an icy sea, especially his ending in which he dives into the sea to visit her) is one big reference to Cygnus Hyoga and his deceased mother Natassia.
His moves are clearly based on Guile's, leading some to wonder whether his missing father is Guile himself or Charlie.
His look, on the other hand, is meant to evoke SNK character Iori Yagami (comparison here). Things would come full circle when Ash Crimson (making his debut in KOF 2003) would further emulate Remy in design, right down to the moveset.
Puertorican fans, because of his look and fighting style, call him the "bastard child of Guile and Morrigan."
Twelve's intro against Necro mirrors the intro against Juli and Juni in Alpha 3, where multiple Twelves (instead of all of The Dolls) fall from to the sky and then disperse, revealing the real Twelve.
This reflects on Twelve's name as well, as each of the Dolls were named after a month of the year in their native language (ergo, there are twelve of them).
Ibuki's 9th color in Super Street Fighter IV bears a striking resemblance to the main character a certain popular ninja manga...
Ryu claims that her ninjutsu is different than the Bushin style, because she isn't a Guy.
Yun and Yang are essentially Gen split into two different characters and then extrapolated.
He's seen as the love child of Gill/Urien and the T-1000 or the Monitor Cyborgs from The Animated Movie.
Also, there is the visual resemblance to Doctor Manhattan which didn't go unnoticed. Capcom saw it as well and lampshaded it with his 8th color palette.
His 5th, golden-color palette makes him look like an Oscar.
His green color pattern combined with his first alternate costume makes Seth look a little like a bald, less bulkier Hulk.
Juri bears more than a striking resemblance to Jolyne Kujo, which have also not gone unnoticed. It helps that Capcom has borrowed from other anime series in the past, including JoJo's.
In a way, she's a Gone Horribly WrongWhat IfExpy of Chun-Li: both are skilled martial artists, both of their fathers tried to take on Shadaloo and died. The only difference is that Bison took it to a higher level with Juri and the end result was, well...
Both of El Fuerte's new Ultra Combos in Super Street Fighter IV are Kinnikuman references. One of them, the Ultimo Spark, is a modified Incomplete Muscle Spark, and the Flying Giga buster resembles Big Body's Maple Leaf Clutch.
He's also the Shotoclone version of Charlie; his projectile attacks are different from Ryu, Ken, and Akuma, just as Charlie's Sonic Boom is different from Guile's. Also, Gouken taught Ryu and Ken their trademark moves, much like Charlie taught Guile his trademark moves. To top it off, Gouken throws his Hadoukens (except for the Denjin Hadouken Ultra) with one hand, just like Charlie throws his sonic booms with one hand.
As something of an Actor Allusion, Toru Okawa (who voices Gouken in IV) previously voiced Ryu in 3rd Strike. His Ultras, the Shin Shoryuken and Denjin Hadouken, were two of Ryu's Super Arts in the III series.
Gouken also borrows several techniques from Akuma: his Tatsumaki Gou Rasen is a watered-down version of Akuma's Messatsu Gou Rasen Super Art from III and his Senkuu Goushouha has Gouken dashing across the stage in a pose similar to how Akuma performs the Ashura Senkuu in EX.
C. Viper's moveset as well as the idea of a combat suit and the shades were actually taken from Captain Commando, Capcom's original mascot, who reappeared in titles such as Marvel vs. Capcom and Namco X Capcom. Not only does she share some similar moves and normal attacks, her third alternate outfit from Super Street Fighter IV bears a not so visible star emblem similar to CapCom's. The fact that Captain Commando takes place in the future of the same Shared Universe has led some fans to speculate that her gear is an early version of what will eventually become CapCom's armor.
Her backstory and appearance also mirror that of Vanessa.
Hakan looks like Darun Mister from the EX series, only with a permanent sunburn and silly hair.
His default outfit looks like a barefoot Mike Haggar, with a different skin tone and hair style.
One of his taunts is "I haven't even begun to fight." This is very similar to John Paul Jones' iconic Badass Boast, "I have not yet begun to fight!"
All the characters in the film do at least one of their signature video game moves while fighting: Guile does his Flash Kick, Ken does the Dragon Punch (delivered as a rather crude uppercut), Vega does his somersault lunge attack, and Ryu performs his iconic HADOUKEN (minus the lasers). At one point while Guile and Bison are fighting, Guile appears to actually back Bison into a wall (which is a common tactic in fighting games).
The entire point of Sawada was to avoid paying royalties to the Bruce Lee estate since Fei-Long is based on his likeness.
The comics turn Mike Haggar into a thinly-veiled Arnold Schwarzenegger, down to his action movies (like "The Eliminator") and catchphrases like "I'll return". This is a natural extrapolation of their pre-existing similarities as gargantuan musclemen turned politicians.
The enemies Fei Long faces in the Chinese sector of the Street Fighter tournament in II Turbo are all parodies of famous Kung Fu movies: there is a drunken fist-using Jackie Chan parody, a parasol-using Jet Li Parody, an old man using the flying guillotine, a woman with long white hair presumably based on the wuxia character, and a masked fighter resembling the title character in the Iron Monkey. Chun-Li fights against martial artists whose styles are all based on animals: Monkey, Crane, Tiger, Snake, and Mantis -- human versions of The Furious Five (which she actually lampshades).