JAPANESE DIFFERENCES
There were often little differences between the versions of Final Fight in Japan and the ones in the US and Europe, and a probably a few other places.
Just about everybody knows that Poison and Roxy were taken out of the of the US/PAL Super Nintendo versions of Final Fight and Final Fight Guy. Instead, we got Billy and Sid, who acted the same but obviously looked a lot different. The reason? Because Nintendo thought that Poison and Roxy were transvestites. They weren't, but what's really strange is that the same thing happened in the Game Boy Advance game, Final Fight One, some ten years later! Why?
In the Mega CD version of Final Fight, Poison and Roxy were left in but were changed slightly and covered up more, as you can see with the above image. Damnd and Sodom still had different names though.
In the arcade this picture of Jessica was shown in the intro. In the world versions of Final Fight, the picture was removed completely, and instead Damnd's face was on all the way through. However in most of the console conversions, Jessica was in but was wearing a red dress.
In the SNES and Mega CD US/PAL versions of Final Fight and Final Fight Guy, Damnd and Sodom were give some god-awful new names. Damnd became the rock hard sounding "Thrasher" whilst Sodom was given the truly bizarre name of Katana. Why would you name your child after a sword? Anyway, the Japanese versions didn't have the name change, as you can see.
The whole Poison/Roxy thing didn't stop, it continued into Final Fight 2. Yup, in the Japanese version there were two females called Mary and Eliza . But over here they were called Robert and Leon and looked a lot different, the most obvious thing being that they were male. They still attacked in the same way though. But just why were they changed anyway? Beats me.
OTHER DIFFERENCES:
In the SNES versions of Final Fight, in the introduction sequence of the Japanese version the music will start playing straight away but in the US/PAL one it starts later on.
Items like whisky and beer are not in the US/PAL versions of Final Fight on the SNES but they are in the Japanese one.