Sometimes, when a game is being made, the developers might come up with a new idea, possibly implement it, but have to remove it from the final version for various reasons. This is also the case with the Batman: Arkham Series. This page tries to list some content found by different individuals either from the game files, early previews or mentioned by the developers themselves.
Batman: Arkham Asylum
- Mad Hatter was planned to appear as a villain on a children's hedge maze. He, and the maze, were scrapped early in production as there was no place for either of them in the game's plot.
- The very first iteration of the game was "a full rhythm action game". The second version was 2D, only the combat was rhythm-based and "involved coloured circles bashing into each other". This eventually evolved into the current Freeflow system.
- During the game's development, another insane enemy was about to appear in the game, the Straight Jacket Henchman. He was going to move in a similar pattern like the other crazed inmates, but would wield some sort of a blunt weapon in his free hand. However, he was scrapped during the early stages of the game, but still made an appearance in the game as the severed head in the jar in one of the offices in the Sanatorium of the Medical Facility.
- Early in development, only Arkham Lunatics were injected with Titan to create the insane Titan Henchmen rather than Blackgate Prisoners and Arkham guards. This also suggests that originally Titan didn't effect a person's mentality.
- Titan Joker's design was originally going to look very different. According to Carlos D'anda: "I had initially envisioned him as a 'spiderlike' creature more than anything... some disjointed, messed up looking monster straight out of an Aphex Twin video or something...." However, he was eventually forced to make Titan Joker look more like the other, more muscular, Titans. 
- Joker's early design featured him wearing a "mad scientist" outfit to coincide with Harley Quinn's "nurse" outfit. But this was changed in favor for a more traditional look.
- The sides of Joker's mouth were originally torn or scarred as well. Though this was scrapped so it wouldn't coincide with Joker's appearance in the live-action Batman film The Dark Knight.
- The Riddler's Cell originally had Red Question marks painted on it's walls. In addition, there was some french writing on the wall, which translates into "I loved, I suffered, now I hate."
- A trailer of the game shows a High Security Henchman emerging from a large container, but in the actual game a TITAN henchman appears on it's place. Either the enemy was changed during production, or the HS henchman was used in the trailer to prevent any pre-release spoilers.
- Several design choices point towards the game originally taking place in rainy weather. It's raining in the opening cutscene, whenever Batman is inside the Medical Facility lightning strikes can be seen, and several guards and inmates are wearing raincoats. It's possible that the game was planned to have rainfall, before it was removed, possibly due to performance issues. In Batman: Return To Arkham, there is now rainfall in free roam, either to address the opening and Medical Facility rain or due to the improved hardware allowing previously unavailable, yet desired, effects.
Batman: Arkham City
- Some game files indicate that Clayface was supposed to impersonate Talia at some point.
- According to the credits, Nightwing is voiced by Quinton Flynn. However, he has no lines on the entire game, hinting that Nightwing was supposed to have a larger role.
- Hacking the game reveals unused Trophy data for the characters Sickle, Mad Hatter Henchman, Reporter, Armored TYGER Guard, Unmasked Batman, Arkham Outcast, and Two-Face Outcasts. Along with leftover Trophy data from Batman: Arkham Asylum.
- Apparently, there was a humorous scene in the Penguin's museum that was scrapped from the game. At the part when Tiny bites into Batman's raft, Batman reaches for a compartment on his Utility Belt labeled "shark repellent". Opening the compartment, Batman pulls out brass knuckles which he then uses to beat Tiny with. A remnant of this idea is still mentioned on one of the game over screens.
- Joker's design on the trailers differs greatly from his in-game design, looking much sicker than on the finalized game.
Batman: Arkham Origins
- The Worst Nightmare suit seen on several cutscenes was originally a playable skin. It was removed because it apparently caused a glitch that interferes with saved game data.
- Batman was originally planned to randomly trip while running and sometimes miss his targets when throwing Batarangs. This was scrapped because it was deemed too irritating for players. Also cut from the game was weather effects, one of which was to be a white out, which would lower visablilty to near zero and make movement only possible with Detective Vision. This was also cut because of performance issues.
- Hacking the game reveals unused data for a Tiffany Ambrose Trophy and leftover Trophy data from Batman: Arkham City.
- Two more Martial Artist variants were designed; Anarky's gang and GCPD. The GCPD variant only appeared on Concept art, and the Anarky variant appeared on the E3 demo, but never appeared on the finalized game.
- A train appeared on a trailer. However, there are no trains on the final version. Why they were cut is unknown, although it could also be related to performance.
- In Multiplayer, Dick Grayson's Robin originally was planned to use Escrima Sticks as shown in some artwork. However, due to time constraints, the developers had to reuse Robin's moveset instead.
- The developers wanted Air Drones to patrol the skies, but didn't know how to implement them. Batman: Arkham Knight does feature air drones, possibly due to the better hardware.
Batman: Arkham Knight
- Some files found from the game files indicate that several more skins were to appear as DLC, but weren't made.
- These files also mention Black Mask and Prometheus. While Black Mask appears on the Red Hood DLC, Prometheus on the other hand was cut entirely from the game.
- A special challenge called "Million Dollar Mayhem" was planned. This mode let players to control Joker, and cause as much destruction and mayhem as they could in 5 minutes, before "sending the bill to Wayne Enterprises". the concept however was cut.
- Originally, Explosive Gel was only going to be used in context sensitive areas and not chosen by the player on a gadget selection display.
- Many speculate that The Botanical Gardens on Miagani Island might have been designed with a predator challenge in mind, as the area has several Vantage Points and Floor Grates for seemingly no reason.
- It appears that Victor Zsasz was originally going to have a bigger role in the game, as a written bio about Zsasz can be found in the game's data. In his cameo appearance on Clock Tower surveillance feed, he reuses his Asylum/City character model, hinting that if he was cut, it happened early on development.
- The playable Red Hood's and Harley Quinn's gadget selection wheels differ greatly in design when compared to the other characters, being positioned slightly to the right with a transparent background. It could be a remnant of an earlier design which was replaced by the current one.
- According to Sefton Hill, the game's credits were planned to include an interactive combat sequence against Rocksteady employees, and each knockdown caused their name and role in development to appear during slow motion.