Justice League's post-production process was extremely rushed due to Joss Whedon's extensive reshoots and that may have hurt the movie in a big way. The filmmaker probably didn't help matters by hiring a new composer in the form of Danny Elfman as his score has been widely criticised from the moment it was released (Batman v Superman's Junkie XL was set to score it before Whedon fired him).
In a new interview, Elfman has shed some light on Justice League's chaotic post-production process and it's no wonder his score ended up being a mess! "I got the call from Joss very last-second," the composer said. "I got the call and it was, ‘You have to decide now and then go to work tomorrow.’"
Elfman also confirms that much of Justice League was being shot while he wrote the score and that he never worked on any scenes which didn't ultimately make it into the movie. That was because things were so last-minute and it resulted in him scoring storyboards as opposed to any actual footage.
"I had a lot of storyboards in place of action. There would be full scenes and then a five-minute sequence of storyboards. Honestly, it was like working on an animated film. I didn’t score any of the unused footage — the movie that came out is the movie I scored, it was just in very rough form." What a mess, eh? That must have been tough for Elfman and it's no wonder his score underwhelmed.