According to the game's illustrator Akira “Akiman” Yasuda in a 2003 interview, Chun-Li's design was initially based on the Chinese character Tao from the animated film, Genma Wars (or Harmagedon in the west). Yasuda then went on to make several additions to the design, which resulted in her appearance in the final game.

"My first idea resembled the Chinese character Tao from the Genma Taisen (Genma Wars) animated movie, with big wide-legged pants. She would also have that front and back apron. The character wasn’t very sexy though, and my design lacked visual impact and personality. So at the 11th hour, I experimented and made a bunch of frantic changes to the pixel art. First I tried giving her bare legs and a bodycon dress. That made her look like a female pro-wrestler, a sort of “fake” kung-fu fighter. It’s a little bit hard to describe in words, but it had a lot of impact, and I decided to go with it and release her to the world this way."

In a 1991 interview with the game's composer Yoko Shimomura published in vol. 62 of Gamest magazine, she was asked who did the voices for the game's characters. She stated that the team asked people at Capcom to perform them, and had about 30 different employees record their voices. She described it as a "kind of a chaotic jumble", and the team chose the best takes from the recordings, but at that point she had forgotten who voiced who. She also stated that the pronunciation for the English voices needed to be correct, so the team asked some non-Japanese people to voice them. In particular, E. Honda's “dosukoi!” line was originally voiced by a foreigner, although the team ended up not using it. They also tried having a man voice Chun-Li's “Spinning Bird Kick!” in a falsetto voice, but ultimately picked something different after more people auditioned.

In a 1991 interview with the game's composer Yoko Shimomura published in vol. 62 of Gamest magazine, she stated that she almost wrote all the songs in the game based on how she pictured each different country in her mind, and also tried to match the music with the stage backgrounds.

In a 1991 interview with the game's planner Akira Nishitani published in vol. 62 of Gamest magazine, he confirmed that in Taiwan, a special version of Street Fighter II was manufactured with only three buttons on a custom control panel. He claimed that the Taiwanese "don't mind if there's fewer buttons, as long as the game is playable." By pressing certain button combinations, such as two buttons at the same time, you can perform different attacks, but due to the limited controls, some moves cannot be performed at all.

Nishitani added that the game is popular in Taiwan as well: "They seem to prefer Street Fighter I/II and Tenchi o Kurau (Dynasty Wars) to Final Fight. It makes sense, being the home of kung fu and all."

Cammy's character, fighting style, and animations are believed by some fans to be heavily inspired by Gally, the protagonist of the 1990 manga Battle Angel Alita.

In a 1991 interview with the game's composer Yoko Shimomura published in vol. 62 of Gamest magazine, she stated that her idea for Dhalsim’s theme was inspired by a CD she owned of Indian and Pakistani music, and that she "may have gone a little too far" in selling the idea to the development team. She also thought using tsuzumi drums in the music would make it sound more Japanese, and more akin to "that fusion sound, the king of music that's great to listen to when you're driving around."

In a 1991 interview with the game's composer Yoko Shimomura published in vol. 62 of Gamest magazine interview, she was asked about the in-game music speeding up when the fighter's health gets low, and if the tempo of the songs themselves was actually speeding up. She responded:

In a 1991 interview with Yoshiki Okamoto published in vol. 62 of Gamest magazine, he was asked how development on the game started. He responded:



Akira Nishitani was then asked if he played the first Street Fighter, and stated:

In an interview with the development team, lead planner Akira Nishitani said that the reason why the attacks change depending on how far away you are from your opponent was because they wanted to implement rapid chains of attack similar to Final Fight.

Computer (CPU) fighters are able to bypass certain rules that human players had to abide by:
•When high blocking, the human player is still vulnerable to low attacks like leg sweeping. However, the CPU is able to block them with a high block and immediately counterattack.
•Human players that become dizzy are immobile for a while, but the CPU can recover in only 1/5 or 1/8 of a second.
•Special moves like Guile’s Flash Kick require human players to input precise button commands to execute (Crouch for 2 second, then hit Up+Kick). But CPU fighters can execute special moves immediately. For example, Guile can execute his Flash Kick by crouching for only a second, or sometimes not at all.
•When a CPU opponent performs a hold, they’re able to tap the button quicker than is humanly possible, thus allowing them to do enough damage to deplete a full life bar by 95%.
•When low blocking, players can block low attacks such as leg sweeps. However, CPU fighters are able to bypass this and land their attacks as if they’re not being blocked.

At one point during the process of drafting the characters, Blanka's skin color was pink. It was changed to green because lead planner Akira Nishitani did not like it.

If The New Challengers release of the game detects that the cartridge ROM is too large or not mirrored correctly, which is usually caused by use of a cartridge copier, the game will completely black out the screen some time after starting a match.

At one point, the development team wanted to implement pressure sensitive buttons similar to those found in certain cabinets of the original Street Fighter, but they decided to go with a 6-button layout because that was the kind of arcade machine that was available to them.

Shin Akuma's Shun Goku Satsu's animation in the Ultra Street Fighter II version is different from that of Evil Ryu and regular Akuma. Additionally, he now has pre-battle dialogue against the player's character.

The Ultra Street Fighter II version of the game removed references to the USSR that were present in previous iterations of the game.

Blanka could originally return to the ground right after hitting an opponent with his Rolling Attack, allowing the player to follow it up with other moves in a combo. This was ultimately changed for the final release.

The team originally wanted to give the AI the ability to change it's tactis depending on who it was fighting against, such as the computer knowing how close to stand to each individual opponent, etc. This feature was removed due to time contraits.

The characters were originally going to recieve more damage when dizzied. This feature was removed due to time contraits.

The team originally wanted to give "weak points" to the characters. When the characters where hit in said weak points, they recieved more damage. This feature was removed due to time contrainsts.

The team originally wanted to introduce character intro animations, but they were scrapped because of lack of memory. The only renmant of this idea is the sequence of M.Bison (Dictador) removing his cape before starting the match.

The team originally wanted to include stage hazards into the game such as projecticles blown by the wind that the player had to dodge, but the idea was scrapped early on.

During early development the team had the idea of the game's story being centered around an abandoned island that had been purchased to host a tournament featuring fighters of all different styles. This early draft of the story is reminescent of the 1973 film Enter the Dragon.

Early sketches suggest that Vega was going to resemble a medieval knight wearing a full suit of armor. He was also simply named "Spanish Ninja" by the developers until he was finally given a name.

During the early development of Street Fighter II, many characters had placeholder names until they were given proper ones:
•Zangief was referred to as “Vodka Gorbavsky".
•Chun-Li was named "Chinese Girl"
•Blanka was called "beast"
•M.Bison (Dictador) was named Washizaki (鷲崎 "Eagle Cape"), likely a reference to the villian of the same name from the manga series Riki-Oh.

During the development of Street Fighter II, an early design for Dhalsim bore a striking resemblance to Ganesha, a Hindu god with four arms and the head of an elephant. His name around that time was Naradatta’, which may refer to a character in Osamu Tezuka’s manga Buddha.

The team originally wanted to give Dhalsim the ability to use the attacks 'Yoga Mummy' and 'Drill Kick' in reverse so that players could retreat. This feature was removed because the computer AI didn’t know how to handle it.

Super Street Fighter 2 HD Remix started out as a remake of Street Fighter Alpha 3. Lead designer David Sirlin felt that Alpha 3's large roster would make the development process more difficult. He also believed that the game's lack of approval by the hardcore community would harm the game's sales, so he pushed Capcom so that they could work on SF2 instead.

David Sirlin also confirmed that the development team scrapped 2,500 animation frames in development because they weren't satisfied with how they turned out.

The team originally wanted to introduce special KO animations depending on how the player finished off their opponent. The only remnants of this feature are a special KO if the player's character is defeated while guarding against a hadouken.

Zangief's headbutt move was originally more elaborated, originally being a throw in which Zangief sent the opponent straight into the air and would then headbutt them on the way down. It was cut due to issues implementing the attack.

Chun-Li originally had a back flip attack, but it was cut due to being too strong and the team not having enough time to adjust it. However, sprites for the move still exist in the game's data, and it was later implemented in SFII: Champion edition.

Two non-playable fighters are shown during the opening scene of Street Fighter II: World Warrior. One punches the other, followed by the screen scrolling up a skyscraper to display the game's logo.

The fighters' names were revealed to be Max and Scott as part of Street Fighter V's "Shadaloo Activity Report" on Capcom's Japanese website.

In the Super Famicon version of the game, a man in a blue coat and hat can be seen in the background of Ken's stage moving his hand up and down in front of his crotch. This was changed in international versions due to the movement making him look like he is masturbating.

On the arcade version of "Super Street Fighter II: The New Challengers", Cammy's ending has an error in her dialogue, her line reads; "WAIT! IF WHAT HE". The end of the line is supposed to read "SAYS IS TRUE...", but it was cut off, even though the whole sentence is still inside the data.

This was corrected in "Hyper Street Fighter II", but with a comma instead of ellipses.

Some fans have pointed out that Ken's theme sounds similar to the Cheap Trick song "Mighty Wings" from Top Gun. Street Fighter 2 composer Yoko Shimomura stated in a interview: "I have heard people say that, and I watched the movie before I composed the song, so I can't deny I may have been inspired subconsciously. But I didn't go into it thinking, 'OK I'm gonna make this song sound like Mighty Wings.'"

On the arcade and Genesis versions of Super Street Fighter II: The New Challengers, Chun Li's ending shows her punching a man with blood spraying from his mouth. In the SNES version the blood was recolored to censor it.

In Zangief's ending on the arcade and Genesis versions of "Super Street Fighter II: The New Challengers", there's a close-up of ex Soviet President Mikhail Gorbachev's face, but it was removed on the SNES.

In the arcade and Genesis versions of Super Street Fighter II: The New Challengers, Balrog's quote when he wins is "My fists have your blood on them.", but on SNES, this was changed to "Get up you wimp!".

In the arcade and Genesis versions of Super Street Fighter II: The New Challengers, characters' defeated portraits show blood and gore. This was removed in the SNES release.

The idea of Street Fighter II Turbo: Hyper Fighting came about as a result of Capcom USA's James Goddard testing the counterfeit "Rainbow Edition" at an arcade to see if it represented a serious threat. He was initially unimpressed by the poor balance, but Champion Edition "felt like it was underwater" after experiencing the faster pace of the counterfeit.

Blanka's Rolling Attack's command was originally charge down, then forward. This felt wrong, as it was different from the rest of the game's commands, and so it was changed.

In the Japanese versions of Street Fighter 2, advice is given to the player on the continue screen. The developers originally considered having a mysterious old man give the advice, but never decided on a design for him, and so the idea was dropped.

It was initially planned for special moves to do more damage the quicker the command was entered.

Akuma has two different endings depending on whether the player beat M.Bison or Shin Akuma. The text in both endings was removed in releases of the game outside Japan.

In every Street Fighter II version in which Vega can be selected as a playable character, the Spanish flag seen in the character select screen is the one that was used during the military dictatorship of Francisco Franco (1939-1975).
This game was released in 1991, 16 years after that flag was declared unconstitutional.

In the first three versions of Street Fighter II, "World Warrior", "Champion Edition" and "Hyper Fighting", Ryu and Ken's Hadoken sprites would sometimes appear orange. Developer Akira Nishitani confirmed that this was added as an Easter egg, and wasn't a glitch as previously thought.

In later versions of the game, starting with "Super Street Fighter II: The New Challengers", Ryu would receive a legitimate orange Hadoken special move called "Shakunetsu Hadoken"

In the original arcade version, Ryu had a winning quote that said, "You must defeat Sheng Long to stand a chance." This was a mistranslation that should have said "You must defeat my dragon punch to stand a chance." Sheng Long has become a running joke with Capcom that has turned into the characters of Akuma and Gouken

In Japanese versions of Street Fighter II, M. Bison is called Vega, Vega is called Balrog and Balrog is called M. Bison. This was to avoid any issues over naming Balrog, the boxer, a name very similar to that of Mike Tyson.

In Super Street Fighter II: The New Challengers, there is an unused graphic in the game with the name "Sarah". This may have been Cammy's early name.

The "Combo" system developed for the game was a bug. A bug in the game's code enabled the player to "cancel" during the animation of some moves by performing another move, allowing for a combination of several basic and special moves. This "combo" system was later adopted as a standard feature of fighting games, and was expanded upon in subsequent Street Figher installments.