* ActingForTwo: In the Mega CD release, Creator/ShigeruChiba voices Gaw and Nuts Cracker. He was only credited for voicing Gaw.
* TheOtherDarrin:
** The 1994 Mega CD and PC Engine releases featured different voice casts. For example, Mail is voiced by Creator/MegumiHayashibara in the Mega CD release and by Creator/MarikoKouda in the PC Engine release.
** For the Drama [=CD=] releases, everyone besides Hayashibara was inevitably recast.
* RoleReprise: Creator/MegumiHayashibara reprises her role as Mail for the Drama CD release.
* WhatCouldHaveBeen:
** When bringing the game to the West on the Platform/SegaCD, Sega initially thought about reusing the engine for a ''Franchise/SonicTheHedgehog'' game called ''Sister Sonic'', about Sonic's long-lost relative. Due to backlash by people who wanted to have a regular Western release of ''Popful Mail'', they decided to just do a straight translation of the game.
** Creator/{{Falcom}} shopped around ''Mail'' as a potential anime series, but none of the studios would bite. A promotional video is all that remains of this concept.
** The English versions of ''Popful Mail'' and the ''VideoGame/{{Lunar}}'' games were considered for the Sega Genesis Mini 2 console, but [[Creator/WorkingDesigns Victor Ireland]], who owns the rights to the English translation, could not come to terms with Creator/{{Sega}} over royalties.
* YouSoundFamiliar: In the Drama [=CDs=], Katyusha is voiced by Creator/MarikoKouda, who previously voiced Mail in the PC Engine release.
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