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Final Fight - Did You Know Gaming? Feat. Two Best Friends Play (Matt)
 
The first boss was named Damnd in the Japanese version, which is similar to "damned", a mild swear word in America. This resulted in Damnd's name being changed to Thrasher in the west.
Contributed by MeleeWaluigi
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Poison's name comes from the rock band of the same name. She wears a hat just like C.C Deville, the lead guitarist, who wore the cap for a while. It has the exact same skull logo on the front.

"Also, we had a woman co-worker who we asked to list as many names as she could think of for our characters. She was really into rock music, so that's why lots of them turned out to be named after band members!" - Akira Nishitani, Final Fight Game Designer (Retro Gamer Magazine Issue 37)
There are actually "easier" and "harder" patterns in Final Fight's difficulty. They happen randomly at a very low chance.
Contributed by Cavery210
At the end of most versions of the game, Guy suddenly attacks Cody.

It was originally believed that Guy beat Cody up because he was jealous that Cody got the girl (Jessica) but in actual fact, Jessica had just called out Cody's name, Cody ignored her and Guy was annoyed at Cody's behavior (The whole point of their quest was to rescue her), so he knocks Cody down to give Jessica a chance to catch up. Furthermore, Guy already has a lover (Rena) and in the game's intro he doesn't seem to know who Jessica is.
Contributed by MightyKombat
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Guy's name was originally spelled "Gay" in early development versions. As director Akira Nishitani put it, the development team wasn't "really aware of English spelling and pronunciation conventions." An unused graphic with the names "Gay, Haggar and Cody" can still be found in the game's code.
Contributed by Cavery210
If the player picks up Edi E.'s gum while they have full life, they'll be awarded 42910 points. This is a numerical representation of designer Akira Nishitani's birthday, September 10th of Showa 42. The year Showa 42 is equivalent to 1967 in the Gregorian calendar commonly used throughout the world.
Contributed by Cavery210
Entering the initials CAP, COM AND GUY on the high-score screen (as the top 3 scores, in that order) and starting a new game will give the player 5 credits instead of 3.
Contributed by DeerBoarDude
The SNES version is missing the character of Guy. A later version of the game was released called Final Fight Guy, which replaced Cody with Guy and made up a new story to explain Cody's absence to the game. The game was sold in stores in Japan and was a rental only at Blockbuster in America.
Contributed by gamemaster1991
In the Japanese version, when you finish the car smashing bonus stage, the car's owner will come out and yell, "Oh, my god!". In the North American version, it was changed to him yelling, "Oh, my car!".
Contributed by gamemaster1991
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Final Fight had a working title of Street Fighter '89, and was intended to be a sequel to the original Street Fighter. The name was changed after the operators stated that the game "was nothing like Street Fighter".
Contributed by gamemaster1991
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Poison, the female thug, was simply intended to be a female gang member to contrast all the large bulky male fighters and add variety to the game. An American playtester working at Capcom objected to the player hitting females, to which Akira Yasuda pointed out that the females were actually transvestites, as stated in Poison's profile that she was born a man, but dresses as a woman. This wasn't enough for North America, so Poison and a recolor of her character, Roxy, were replaced with two male characters called Billy and Sid on the Super Nintendo.

Poison was also censored in the Sega CD version to increase the size of her shirt, so that less of her breasts were revealed in several poses.
Contributed by DidYouKnowGaming