* ActingForTwo: Asha, Pepelogoo, Prapril XIII, and other 26 characters had been voiced by single voice actor, {{Creator/Fairouz Ai}}.
* FanTranslation: To be expected of a game that is part of a series that usually got translated. It received an official translation nearly two decades after its Japanese release. Comparing the two, it's obvious the FanTranslation made up several lines that weren't in the original, left several Japanese characters which could've been translated just fine, and has several inaccuracies. One of the most infamous is the book indicating that Shion mysteriously disappeared after the events of ''Monster World'', which is nowhere to be found in the original.
* MarketBasedTitle: The remake retitles ''Monster World IV'' to ''Wonder Boy: Asha in Monster World'', possibly for branding purposes.
* NoExportForYou: ''Monster World IV'' was only available in Japan initially. In 2012, Sega released the game as a download for the Platform/{{Wii}}, Platform/PlayStation3 and Platform/Xbox360. Amazingly, the game came with a complete English translation, marking the only time an import Platform/VirtualConsole game was translated in full for English-language gamers (other imports on the service were left untouched).
* SuddenlyVoiced: The 2021 remake marked the first time in the series to have a voice acting for the cutscenes and [[ManOfAThousandVoices some of them are done by one person]].
* WhatCouldHaveBeen:
** ''Monster World IV'' was to include a gender option, with the male character having [[https://www.facebook.com/MWFan2012/photos/482498251765245/ artwork]] and [[https://twitter.com/maki_ohzora/status/807131879941906432 sprites]] by Maki Ohzora, and a working name ("Eusha", similar to Asha and meaning brave man). Due to cartridge constraints, he was canned in favor of giving the female lead the spotlight, but his design did get repurposed as an NPC. This idea would later be implemented in the remake of ''The Dragon's Trap''.
** Additionally, there were going to be other kinds of weapons to use, such as axes and bows.
** Jin Watanabe [[https://www.facebook.com/MWFan2012/photos/a.482498248431912/488236051191465/ composed music]] expecting a tropical stage, but as an ocean stage did not return in this game, it ended up getting scrapped as well.