One of the game's trophies is called "JULLIET51" which is earned by doing 51 dropkicks, the name is a reference to the game director Suda 51.
James Gunn later collaborated with Tara Strong in Guardians of the Galaxy Vol. 3.
James Gunn brought his collaborators including Michael Rooker and Sean Gunn to provide voice acting for the English version. He also did the voice directing.
Suda 51 came up with the concept and he and Warner Brothers hired James Gunn to write the game. One of the reasons why Gunn was hired is to make the game more Western.
James Gunn previously wrote the Dawn of the Dead remake before he got hired to write this game.