Tarkus and Bruford are The Big Show and Chris Jericho respectively. For Bruford, he's mostly heel Y2J Jericho, but his death scene references Jericho's old "Lionheart" gimmick.
Awesome Music: The theme song used for the Stardust Crusaders OVA, a cover of "Holy Diver" by Ronnie James Dio (The first half of Dio's namesake), preformed by Killswitch Engage. The original is used at the end of Dio's proper debut episode as well.
When Dio pulls an Out of the Inferno with Senator Philip's body, the intro to "March of Mephistopheles" by Kamelot is used to startling effect.
Jotaro: Wow Dio, looks like I just violated your manhole..... cover.
Also gets lampshaded and defied when Dio's explaining what he did to Joseph.
Dio: I, Dio, blew any chance of him living out of the water. I, Dio, sucked him bone dry. I, Dio, reached around and— you're just getting me to say a whole bunch of really gay sh*t now, aren't you.
Jotaro: Heh heh, yeah.
Growing the Beard: Most fans agree that the series noticeably jumped in quality either on episode 4 or 6, depending on who you ask.
Genius Bonus: In episode 8, Polnareff's quip on how Vanilla Ice is about to be under pressure before killing him refers to his namesake getting into legal trouble, having been acussed of sampling the bassline of Queen song "Under Pressure" for "Ice Ice Baby".
Harsher in Hindsight: Speedwagon, after being hit by Zeppeli, states that he'll never have kids, which would explain things.
Hilarious in Hindsight: Speedwagon at the end of the comment special, commits that he has tanning oil in case of encountering half naked men. Years later, he meets the Pillar Men who all qualify for this.
The bonus video "Doppio was phone?" has a guy drunk calling Hirohiko Araki and asking if they would ever make another Jojo anime. It took two and a half years, but he got his wish.
Jotaro notes that "Fountain of Blood" would make a cool band name. The name of the 2nd OP for the anime is named "Bloody Stream".
Love It or Hate It: Episodes that prominently feature Speedwagon, considering his voice is a deliberate Most Annoying Sound inspired by a similar Pops from Regular Show. People either love it and think it's a hilarious and witty take on the character, or hate it because it's long worn out its welcome and is just too annoying to be funny.
Made worse by the fact that Dio didn't even need the blood: he just did it For the Evulz.
When Jotaro seemingly gets blown up, Dio gives a surprisingly creepy monologue about the new world he's going to set up, storyboarded with disturbing art and ominous music.
Dio: A world ruled by me, a world ruled by fear. A world where the times of unity, peace, and light will be cloaked by the sheets of hate, war, and darkness. A world where hellfire will be considered a safe haven. A world where the streets will run a river of blood, with the corpses of those who would defy me: they will be boats to the crows, and the rats, and the vermin: gnawing and picking at their flesh. A world in my hands, ruled by me, ruled: by I, DIO!
Making it worse is the screams of the people in the picture where Dio mentions that hellfire will be considered a safe haven. Then: "Why can't I move?"
J. Geil is creepy as hell in this adaption, raping Polnareff's sister twice (with one of those times coming after her death), and Hol Horse mentions that J. Geil has been bragging about it. Then he proves to be Dangerously Genre Savvy by forcing the heroes into a Sadistic Choice: either be killed by his Stand, or to kill innocent civilians... and still die by his Stand. And he's played completely seriously.
And then we meet Enya, who forces Hol Horse to shoot himself in the head after stabbing him in the arm. Why? She (wrongly) claims he abandoned her son, and she's going after anyone who was involved. Anyone.
Joseph's description of the picture he offers D'Arby is rather.... descriptive.
Joseph: That's a picture. Of me. Sitting on a couch. With my legs spread open. Naked. This picture was on the cover of GDILFs Magazine's 'Top Ten Sexiest, Most F***able Grandpas. I was number one. Beating both Monkey D. Garp from One Piece, and Uncle Iroh from Avatar.
D'Arby: How...recent...is that picture?
Even more hilarious/disturbing is the fact that there really is a picture out there that matches that description quite closely, despite it being unlikely for Antfish to have inspiration for the joke from it.
N'Doul's death scene of all things, especially when the sad music starts up and N'Doul relates his tragic backstory to Jotaro. Sure it hits Mood Whiplash when Jotaro points out that said backstory was lifted from a flashback from Ray, but it goes back to emotional when Jotaro buries him and wonders if they could have been friends.
A minor one in the Comment Special of all things. Dio's response to Jotaro's dig at the fact he has no real friends showed some serious insecurity. It becomes funny almost immediately afterwards, but it was clear Dio was actually pretty darn hurt by that observation.
Jotaro: You're a jerk...because you don't have any friends.