During the 2nd demo of the game, the situation finisher (stage fatality) in Joestar Mansion featured a defeated character getting impaled onto The Love Goddess's statue. This was modified before the final release, with the screen turning white before impalement.
Contributed by ZpaceJ0ck0
In the Naples Station stage, there is a sign displaying one of Araki's previous mangas, Gorgeous Irene.
Contributed by ZpaceJ0ck0
The cover of the game is a homage to the sixth volume cover of the third story arc of the series, Stardust Crusaders.
Contributed by ZpaceJ0ck0
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Originally Stroheim's default outfit was his Nazi uniform, with the cyborg one being his alternate. The Nazi costume was completely removed in the western releases, thus making his default outfit the cyborg one.
Contributed by ZpaceJ0ck0
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A 2016 Ultra Jump interview details the process that went into deciding which characters to feature in the game. The developer claims that there were 120 characters put up for consideration and that the list was gradually shortened to 80, then finally 52.

Leone Abacchio made it up to testing, but they had problems getting Moody Blues to work with the game. Since Abacchio can't really fight in a straightforward way, the developers had to come up with a system where he would replay things that had happened in the stage and thus rely completely on his opponent's power to battle. However, he was eventually dropped because the player couldn't control him precisely.

Besides Abacchio, several others nearly made the cut including Ringo Roadagain, Tarkus, Bruford, "people from Morioh", and "a bunch of others".
Contributed by ZpaceJ0ck0
The DHA for Mista and Giorno seems to be a reference the White Album fight, particulary the way that Giorno appears from behind and jumps high into the air until he is directly above the opponent, then stomping down on them several times with Gold Experience, as well as the quotes "Resolution isn't all about sacrifice" from Giorno and "My true resolve begins here!" from Mista. The firing pose from Mista (which originates from the same fight), however, was used for Narancia's/Mista's DHA instead.
Contributed by ZpaceJ0ck0