- Beam Me Up, Scotty!: Many have misquoted or misinterpreted Mark Hamill as saying this game will be the last time he plays The Joker. He clarified that what he meant was he wouldn't continue playing The Joker if he felt that he couldn't top his performance, he wanted to leave on a high note. He has since played the Joker again on multiple occasions.
- Blooper: As the generator slams Clayface into the Lazarus Pit and explodes, the vial holding the cure is in Batman's left hand, but when he comes to, it's in his right one. Until Arkham Knight confirmed the Joker died, some people speculated that it was intentional, and the Joker took some of the cure and was faking his death. After Knight, though, it's become clear that it was indeed a screw-up.
- Development Gag: At one point, Batman overhears thugs talking about the rumor that Harley Quinn used to be a man. Harley Quinn was actually motion-captured by a man, and they even released a fake reveal trailer to tease fans about it.
- Fan Nickname:
- The Other Darrin: Tara Strong replaces Arleen Sorkin as Harley Quinn, David Kaye replaces Tom Kane as Commissioner Gordon, and Grey DeLisle replaces Tasia Valenza as Martha Wayne. The latter two are perplexing since, as noted above, Tom and Tasia returned from the first game to reprise the respective roles of Quincy Sharp and Poison Ivy.
- Playing Against Type:
- Talking to Himself:
- Nolan North voices both The Penguin and provides the voices of several randomized inmates. It's not unheard of to hear Nolan North berating his Mooks about how much they suck, only to hear Nolan North reply "You heard Penguin! Let's move!"
- Hush, who has being-Bruce-Wayne's-evil-double as part of his gimmick, is also voiced by Kevin Conroy.
- Viral Marketing: Starting in early October 2011, major YouTube TheGameStation affiliates Husky Starcraft, OMFGcata, TotalHalibut, and the Yogscast left mysterious Riddler question marks in their daily videos: Each one linked to an unlisted YouTube video part of a four-part audio involving Professor Strange and Two-Face that promoted the game and its Facebook page.
- Voices in One Room: Kevin Conroy and Mark Hamill recorded their lines together for the cutscenes where Batman and the Joker interact.
- What Could Have Been
- In an interview, director Sefton Hill said they wanted to include a reference to the infamous Bat-Shark Repellent Spray from the Adam West seriesnote , but ended up nixing it because they felt it was a Level Breaker. There's still a subtle reference; if you get killed by the shark, one of the possible hints reminds you to remember Batman's shark repellent: a flurry of blows to drive it off. In one room, you can listen to the Riddler mutter about ways to take down Batman, and ponders taking Penguin's shark, only to say that there are "too many variables", and that Batman likely has some sort of "shark contingency".
- The plot itself borrows ideas from Knightfall and Batman: No Man's Land, among other famous Batman stories. A lot of the Joker/Batman dynamic is reminiscent of The Killing Joke.
- Arkham City was released the same day as the Animated Adaptation of Batman: Year One and shares a lot of the same voice talent: Grey DeLisle (Catwoman, Vicki Vale, Stacy Baker, Martha Wayne) is Barbara Eileen-Gordon and Vicki Vale, Steve Blum (Killer Croc and Sickle) is Stan, Fred Tatasciore (Bane, Solomon Grundy and Mr. Hammer) is Arnold Flass and Johnny Vitti, and Danny Jacobs (Victor Zsasz) is Flass's lawyer.
Trivia / Batman: Arkham City