William A. Zeppeli's backward running animation. There are no words for how goofy it looks.
Joseph's counter taunt special. He says "Your next sentence is: <opponent's taunt>". Then the opponent is forced to taunt and his/her "taunting panel" appear, then they realize what Joseph did and their "taunting panel" is changed to their "being taunted panel".
Even funnier is how he literally imitates Part 3 DIO's "WRYYYYYYYYYYYYYYYY!" and Valentine's "DOJYAAA~N!"
Made even more funny how imitates the way Iggy chews his gum.
Best of all is how he imitates Baoh's "BARUBARUBARUBARUBARUBARU!", and Baoh being shocked at Joseph's correct guess... despite the fact that Baoh cannot say anything else in his battle form.
Speaking of Joseph, the Western release of the game does a good job of finding a way to deal with his old "Happy, joy-py, nice to meet you-py!" taunt line, by changing it to a cute little Spoonerism instead: "Damn meased to pleet ya!"
His GHA. Josuke heals his opponent to full health, then batters them so badly, they're worse off than before. Especially in the case of Johnny. Josuke's heal allows him to stand again, but the ensuing beatdown cripples him once more. Looks like the only thing worse than insulting Josuke's hair is mockingly complimenting it. Here's the link.
Giorno: Has the balls to claim his hair's better arranged. The same Giorno with a batshit ridiculous @@@ hairdo.
Johnny: Dryly and sarcastically compliments said hairdo, saying it looks "super great." But of course, Josuke detects sarcasm and gets his powerup anyway.
Baoh: Since Ikuro/Baoh can't talk properly, the narrator speaks for him claiming that Baoh doesn't like how Josuke's pompadour smells. Yet Josuke still figures it out, gets pissed off and takes it out on poor Ikuro.
The last part of Okuyasu's super move. After a painful beatdown with The Hand, Okuyasu gives his opponent a badass glare and a smirk...then a flowerpot comes out of nowhere and whacks him in the face.