What Could Have Been / The Flash (2023)

• Ryan Kwanten, Matthew Fox and Scott Porter were considered for the part of Barry Allen before Ezra Miller was cast.
• Rita Ora and Lucy Boynton screen-tested for the role of Iris West before the casting of Kiersey Clemons.
• Rachel Zegler and Bruna Marquezine auditioned for the part of Supergirl before Sasha Calle was cast. Zegler and Marquezine would eventually go on to portray Anthea and Jenny in SHAZAM! Fury of the Gods and Blue Beetle respectively.
• Phil Lord & Chris Miller were the first choice to direct the movie before Andrés Muschietti was hired. However, Lord and Miller turned down the offer due to scheduling commitments to Artemis.
  • Seth Grahame-Smith, Rick Famuyiwa and John Francis Daley and Jonathan Goldstein were each set to direct the film during pre-production, but dropped out of the project citing Creative Differences over the script.
  • Robert Zemeckis, Matthew Vaughn, Jordan Peele, Sam Raimi and Marc Webb had discussions to direct the movie as well before Muschietti was hired. Zemeckis was previously approached to helm Man of Steel before Zack Snyder was hired.
  • Warner Bros. also briefly reached out to Ben Affleck about directing the film before he decided to solely reprise his role as Bruce Wayne in it instead.
• Jeffrey Dean Morgan (Thomas Wayne in Batman v Superman: Dawn of Justice) expressed interest in playing Flashpoint Batman (and Lauren Cohan — Martha Wayne in the same film — was likely to be his Joker) before the decision was made to instead use Michael Keaton's Batman.
• Ray Fisher was intended to reprise his role as Cyborg in multiple iterations of the script, with several early drafts featuring him as a co-lead. Over the course of development, the Cyborg role was decreased in prominence as the scale and focus of the movie shifted, but the character was still meant to be present. Fisher later spoke out about production issues with the reshoots of Justice League, claiming multiple people enabled on-set abuse, which was subsequently investigated. Fisher later accused Walter Hamada — who took over DC Films after Justice League, a film which he had no involvement in, and set up the investigation — of covering up for several parties (including then-DC Films head Geoff Johns and WB executive Toby Emmerich) after only reshoot director Joss Whedon was found to be at fault by an impartial judge. After Fisher publicly announced that he would never work on anything produced by Hamada on social media (who had his contract re-upped days after the statement, though following the heavy restructuring by Warner Bros. Discovery, Hamada would announce to step down after the release of Black Adam), it was confirmed via the press that Fisher would be written out of The Flash, with the role not being recast for the film. Fisher also reportedly could not come to an agreement to the finances of his appearance prior to turning down the project.
• As mentioned above, Billy Crudup was set to reprise his role as Henry Allen until scheduling meant that he couldn't appear, making a replacement actor necessary.
• Zack Snyder's outline for the second and third Justice League movies in a planned five-movie story arc suggested that Captain Cold would've been part of the film as a major villain, and would later be recruited by Lex Luthor as a member of the Legion of Doom after having been imprisoned at the end of The Flash.
• The Batgirl film directed by Adil El Arbi & Bilall Fallah that got cancelled in post-production by Warner Bros. Discovery in August 2022 was supposed to follow up on this film with Michael Keaton as Batman once again, as was a proposed Batman Beyond film that would've seen Keaton's Bruce Wayne mentoring Terry McGinnis and reuniting with Michelle Pfeiffer's Selina Kyle.
• It was reported that, had Ezra Miller not stopped their controversial behavior and cleaned up their act, Warner Bros. might have pulled the unprecedented move of scrapping the film altogether, in spite of sinking nearly $300 million into it, similar to what ended up happening to the Batgirl film that got cancelled in post-production in August 2022. Given the film's final fate as a Box Office Bomb, many analysts suggest they probably should have.
• As mentioned above, Henry Cavill's Superman was meant to cameo in the film after Walter Hamada was ousted from his role as the head of DC Films and after Cavill returned in The Stinger of Black Adam, but his scene wound up being cut after James Gunn took over DC Studios and Cavill subsequently exited the franchise. However, a CGI recreation of Cavill winds up appearing in Barry's first travel back through time.
• The Muschietti siblings had a large list of cameos considered for the film, but a few that didn't make it into the film were Lynda Carter reprising her titular role from Wonder Woman, Grant Gustin reprising his role as Barry Allen from The Flash and even Marlon Brando's Jor-El from Superman: The Movie and both Cesar Romero's Joker and Burgess Meredith's Penguin from the campy Batman series of The '60s, though those three would have likely been featured through Stock Footage due to the actors having passed away long ago. Romero's Joker does end up making an appearance in the final film, via archive audio.
  • According to Andy Muschietti, Adam West's cameo was nearly axed but he fought against that because of his personal love for Batman due to how often he and his sister Barbara saw the show's reruns in their native Argentina.
• Due to the purchase of WB parent WarnerMedia by Discovery that occurred while the film was in production, three separate ending scenes wound up being shot:
  • In the original ending, Barry returned home after seemingly resetting the timeline, only to discover Supergirl and the Michael Keaton version of Bruce Wayne at the courthouse, with the two implicitly having replaced Superman and the Ben Affleck Batman in the Close-Enough Timeline. This was meant to set the two up to appear in future movies such as Batgirl, where Keaton was supposed to reprise his role.
  • After WM was purchased and Walter Hamada exited the company, the ending was redone to add appearances from Henry Cavill as Superman and Gal Gadot as Wonder Woman at the courthouse, establishing that Superman still existed despite Supergirl and the Keaton Batman now being part of the DCEU. The scene was shot in secret alongside Cavill's Black Adam cameo in anticipation of a potential Man of Steel sequel.
  • After James Gunn and Peter Safran became the new co-heads of DC Studios, all of the previous courthouse cameos were axed due to the impending reboot, with Gunn planning to completely recast Superman and Batman for Superman: Legacy and The Brave and the Bold, respectively. With neither Keaton nor Affleck planned to stick around as Batman, the decision was made to bring back George Clooney as another alternate Bruce Wayne in order to maintain the Bait-and-Switch premise of the original ending, albeit with a different outcome.
  • Earlier screenings had a slightly different version where the Bruce Wayne that Barry sees isn't shown onscreen, with an immediate cut to black after having the same reaction. This is likely because of the tumultuous production leaving which Batman it would be up in the air.
• The Stinger for the original film was changed as well. Originally, it was supposed to feature Barry trying to explain the timeline changes to a drunken Aquaman, who would act as though he'd known Supergirl for quite some time and had never heard of Superman, cementing that Superman had been erased from the timeline. Upon returning home, Barry would find an S.O.S. message from the Ben Affleck version of Batman, who had been misplaced in the multiverse due to Barry's actions. All of this was meant to eventually lead to a film adaptation of Crisis on Infinite Earths, with Affleck presumably returning as Batman one more time alongside Michael Keaton. While the scene with Affleck was filmed, it was ultimately cut from the movie, with the theatrical release instead using an altered version of the the conversation between Barry and Arthur as the post-credit scene.
• Had Zack Snyder remained a part of DCEU, Nora Allen's killer would have been revealed to be the Reverse-Flash, and he would have been The Man Behind the Man for many of the franchise's villains.
• There was also reports around January 2023 that WB had reached out to Christian Bale to possibly reprise his role as his Batman from The Dark Knight Trilogy for a possible cameo, but it was likely turned down, as Bale has stated he would only don the cape again if Christopher Nolan was involved. Considering the reports was around the same time the last of re-shoots took place with the reshot ending, including George Clooney's Bruce Wayne, it's very likely this surprise cameo was intended for Christian Bale had he accepted.