Trivia: Originally, famed director Steven Spielberg was attached to direct the film with Will Smith reportedly in talks to play the lead. At this point in development, the film was going to be a more direct adaptation of the original Japanese manga, which differed greatly from the 2003 Korean film adaptation. However, legal issues forced Spielberg and Smith to withdraw from the project. Eventually the legal issues were settled, but the studio had subsequently decided to drop the idea of adapting the manga and instead decided to do a more direct remake of the Korean film due to its critical acclaim and strong cult-following.
Trivia: Spike Lee had a completed director's cut of the film that ran about 140 minutes in length. However, the studio got cold feet over the film and its dark subject matter, and the producers forced the film to be cut down by over 30 minutes for the theatrical release, much to the dismay of director Spike Lee and star Josh Brolin. (Many sequences of important plot character development were reportedly removed, and even the "single-shot fight sequence" was edited down by the studio) Both Lee and Brolin have expressed frustration by the forced editing, to the point where Spike Lee refused to use his standard unique credit ("a Spike Lee joint") in the film's credits, instead opting for the more generic "a Spike Lee film", as he felt the theatrical cut didn't embody his vision of the film. Brolin has stated that he believes Lee's director's cut is a significantly better film than the theatrical edition.
Trivia: At the beginning of the film, we see Joe buying a "rubber ducky" for his daughter from a female street vendor. The street vendor is wearing a set of "Angel Wings" on her back. This is a reference to the original Korean film, in which the lead character had bought his daughter a similar set of "Angel Wings" to wear.
Trivia: The passing reference to "The Count of Monte Cristo" made right before Joe kills a guard at the "prison" is a small nod to the original Korean version of the film. "The Count of Monte Cristo" is referenced and paid homage to several times during the original film.
Trivia: Four major members of the cast are all known for their roles in multiple films in the Marvel Cinematic Universe. (Appearing in three or more films each). Josh Brolin played Thanos, Elizabeth Olsen played Wanda Maximoff, Samuel L. Jackson played Nick Fury and Pom Klementieff played Mantis.