* AscendedMeme: "Bimmy", a misspelling of Billy's name in the 2-player intro to ''Double Dragon III'' (NES), is reused in ''DD Neon'' as a pair of Abobo-sized mutant clones of the Lee Bros. named "Bimmy and Jammy": they also have the [[BossSubtitles Boss Subtitle]] "Mistranslated Mutants" to make it even more obvious.
* BadExportForYou
** The American version of the third arcade game added item shops where the player could purchase new characters, weapons, and new moves by inserting more tokens into the cabinet. In the Japanese version, the non-Lee characters are selectable from the start, weapons are simply found on the ground, and the special moves are usable from the get-go. The only trade-offs are the fact that the Hurricane Kick is harder to pull, and there's no way to increase one's max health and attack speed like in the American version.
** ''Super Double Dragon'' is based on an earlier build of the game compared to its Japanese counterpart (''Return of Double Dragon''). Thus it's missing a few moves (such as the ability to catch your boomerangs during its return or change between moves), the Options menu, a few tunes, and the last two levels of the final stage.
* FanNickname - The final boss in the first game is nicknamed "Machine Gun Willy", for obvious reasons. This also serves to avoid confusion with this game's run of the mill {{mook|s}}, Williams.
* HeyItsThatVoice
** In the PC Engine version of ''Double Dragon II'', Billy and Jimmy were voiced by RyoHorikawa and NobutoshiCanna, who were also the voice of Kunio and Riki respectively in the PC Engine version of ''[[RiverCityRansom Downtown Nekketsu Monogatari]]''.
** In the Neo-Geo game, Billy and Jimmy were voiced by HikaruMidorikawa and KanetoShiozawa, Marian is voiced by Yuko Koyama (Helena Douglas from ''DeadOrAlive'') and the late DaisukeGouri voices Abobo and Burnov.
* ManualMisprint
** The manual for the first NES game gives out incorrect inputs for the Elbow Punch and Spin Kick, suggesting that these moves were planned to be performed differently at some point. The manual also claims that Abobo likes to throw bombs (actually a mistranslated reference to an "atomic suplex" move [[DummiedOut he was supposed to have]]) and spells Rowper's name as "Lopar".
** The English manual for the Master System version has the names of Jeff and Willy switched (compare the [[http://www.smspower.org/Scans/DoubleDragon-SMS-US-R-Manual?gallerypage=10%2F11 English manual]] with the [[http://www.smspower.org/Scans/DoubleDragon-SMS-JP-Manual?gallerypage=13 Japanese one]]). Although the name "Willy" seems more appropriate for a head-swapped evil version of Billy and Jimmy than "Jeff" in retrospect, so it's debatable whether this was a mistake or an intentional change.
* NamesTheSame: Jimmy Lee shares his name with a RealLife comic book artist!
* PortOverdosed: Exceptionally so. Almost every home computer and console of the 80s got a version and the original game has been remade numerous times, even for [=iOS=].
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