In April 2014, it was announced that Snyder would be directing the film with a script by David S. Goyer. In July, Warner Bros. was reportedly courting Terrio to rewrite the script, after having been impressed with his rewrite of Batman v Superman: Dawn of Justice. In October 2014, Warner Bros. originally announced that the film would be released in two parts, with Part One releasing on November 17, 2017, and Part Two on June 14, 2019. Snyder would direct both films. However, in June 2016, Snyder announced that both films would be two stand-alone stories. In July 2015, EW revealed that Terrio had completed the script for Justice League Part One. By June 2016, Henry Cavill, Ben Affleck, Gal Gadot, Jesse Eisenberg, Jeremy Irons, Diane Lane, and Amy Adams were all confirmed to reprise their roles. Ezra Miller, Ray Fisher, Jason Momoa, Amber Heard, and J. K. Simmons were all added to the cast. With a budget of $275 million, Principal photography commenced in April 2016 and ended in October 2016. Locations included Warner Bros. Studios in Leavesden, England, as well as London, Scotland, Los Angeles and Djúpavík, Iceland. In May 2017, extensive reshoots took place in London and Los Angeles, with an additional budget of $25 million. Snyder hired Joss Whedon to write scenes for the reshoots. In the same month, Snyder left the project following the death of his daughter. Whedon then took over the reshoots and the remainder of post-production. Snyder received sole director credit for the film, with Whedon receiving a screenplay credit in post. In addition, Danny Elfman took over from Junkie XL to score the film. Due to the running time backlash of Batman v Superman: Dawn of Justice, Warner Bros. demanded the film come under 2 hours. The final running time for Justice League is 120 minutes. Making the film the shortest DCEU film to date.
It features an ensemble cast that includes Affleck, Cavill, Gadot, Miller, Momoa, Fisher, Irons, Adams, Lane, Simmons and Ciarán Hinds. Though the cast gave performances that would silicify as the definitive cinematic iterations of their comic-book counterparts, the lack of characterization failed to make the audience root for them when they're off saving the world.
After decades of buildup, Justice League has finally arrived and it is horrendously average. Even after its two hour running-time, audiences will leave the theatre unsatisfied. The film has unquestionably squandered the potential of its source material and cast.
Simon says Justice League receives: