Ascended Fanon: How Akuma was conceived. EGM created Sheng Long (the would-be Gouken) for one of their infamous April Fools' articles and caused fans to swarm to arcades to find him. Capcom USA ended up calling Capcom of Japan about this secret boss character, and so they decided to go with it and add in Akuma.
Cash Cow Franchise: A cash cow within a cash cow, the II series is the most well-known and successful sub-series in the Street Fighter franchise. The SNES port of the original remains Capcom's best-selling game.
E. Honda's Sumo Squat is also known as the "Ass Slam".
Mexican gamers gamers calls E. Honda as "Porky" or "Super Porky" (after a famous Mexican wrestler) since Honda is fat and his ramming head-butt attack (the famous "Dosukoi") sounds like he's saying "oink oink" instead in Spanish.
Guile, "The Family Man".
"The First Lady of Gaming" for Chun-Li, which became canon as of Street Fighter IV. Also "Thunder Thighs" and Chunbuns.
More like Fan Abbreviation, but many fans just call Zangief as plain ol' Gief. Also "Blue/Green hand" for his Banishing Flat.
Balrog, Vega and M. Bison are called "Boxer", "Claw" and "Dictator" in international tournament play to avoid confusion caused by the name switchups from the Japanese to the English versions. In Japan, they were known as M. Bison, Balrog and Vega. When Capcom was localizing II for America, there was worry that Mike Tyson might sue them because of Balrog's resemblance to Tyson; thus, the name switch. Also, Vega wasn't a very menacing name, so it went to "Claw" (Vega/Balrog).
Balrog has Rog and Barlog, the latter coming from a misspelling on some of the game's own cabinets.
Vega has "Matador", "Bull Fighter", "Cage Fighter", and "Assassin".
The full title of Street Fighter II′: Champion Edition in Japan is Street Fighter II Dash: Champion Edition. However, the word "Dash" is not spelled out, but represented on the game's logo by a prime mark (an apostrophe-like symbol used in mathematics to indicate derivatives). The prime symbol still appears on the title screen in the overseas versions, but Capcom USA didn't understand its significance and simply referred to the game as Street Fighter II: Champion Edition on promotional materials.
Likewise, Street Fighter II′: Hyper Fighting is known as Street Fighter II Dash Turbo: Hyper Fighting in Japan (the word "Turbo" did not appear in the overseas versions). The SNES version is simply known as Street Fighter II Turbo: Hyper Fighting in all regions.
The first of the two Mega Drive/Genesis ports is known as Street Fighter II Dash Plus: Champion Edition in Japan and Street Fighter II′: Special Champion Edition everywhere else.
Super Street Fighter II Turbo is known as Super Street Fighter II X: Grand Master Challenge in Japan.
Sequel Displacement: One of the biggest cases ever. The "II" was the only hint to many that this was not the first game in the series.
Talking to Himself: The laziest case in the series. Everyone not named Chun-Li had the same voice set. This was fixed in Super.
Throw It In: Since Dhalsim and Guile were the only members of the cast to have a family at the time, Dhalsim's son Datta and Guile's daughter Amy were made pen pals, a plot point that resurfaces in IV (Datta hears from Amy that Guile has left on a mission, informing Dhalsim that there's something rotten in the state of Denmark).
Right off the heels of the Mike Tyson ear bite, rumors persisted that you could become a Cool Loser by cancelling Boxer's Megaton Punch into a hidden Super Combo just as the punch lands. Rotate the controller full-circle twice and hit all three buttons and Boxer will lock his opponent in a headlock and start biting until Edi. E busts Balrog and carts him off to jail, forfeiting the match.
Ascended Meme: In Super IV he gets a new Ultra called Dirty Bull which, before AE, was two full-circle controller rotations and involves illegal boxing maneuvers such as sucker punching, stepping on someone's foot, and clinching.
Two of the four new characters in Super Street Fighter II were going to be head swaps of each other: namely Fei Long and an unnamed rival. James Goddard, a Capcom USA employee who previously worked on Hyper Fighting and Saturday Night Slam Masters, was against the idea of having another pair of head swaps, since he believed that having a completely unique character instead of another head swap would add more variety to the game. The character he came up with to replace Fei Long's rival was none other than Dee Jay, who was modeled after Billy Blanks.
Cammy's original name might have been Sarah, as there's unused character text in the code of Super Street Fighter II with that name.
Super Turbo had several different subtitles before it's final name. Some early promos had it listed as Super Street Fighter II: The Ultimate Championship.
Originally, characters were supposed to take more damage when being hit while in dizzy mode. It was removed for balance issues, though a glitch was accidentally left in The World Warrior where Ryu would take more damage at one frame of his dizzy animation.
There were plans for weak points on certain characters to hit for more damage as well, though it was scrapped.
Juggle combos were going to be implemented much early on but the development team felt the time wasn't right for it. One remnant can be seen in Dhalsim's juggle glitch.
Instead of holding backward then pressing forward, the input for Blanka's Rolling Attack would have been holding down then tapping forward, imitating the idea and feeling of curling up then suddenly springing forward.
Projectiles were originally planned to be able to duck under.
Originally on the game's continue screen, the (Japan only) advice that appears on the bottom would have been dispensed by a mysterious old man.