The voice of Superman is played by Sam Daly. Sam's father, Tim Daly, previously voiced the role of Superman in the animated TV series and various DC animated movies.
Deathstroke's ship is named Ravager. This is a nod to the comic books, where his daughter is code named The Ravager.
The film features a number of cameos including, but not limited to, both aqualads, Orm Curry (oceanmaster), Clayface, Icicle, Goldface, as well as references to Captain Singh, Wally West, Dick Grayson and Harvey Dent on top of many others
At the beginning of the film Barry is seen running toward the front door of his home. The home is drawn to look exactly like the home of Marty McFly in Back to the Future. Marty also inadvertently ruined his timeline and was forced to go back and repair the damage to set things right.
Jennifer Hale voices Barry Allen's girlfriend Iris West in this film. Ironically enough, she voices one of the Flash's enemies, Killer Frost, in multiple DC projects, including the Justice League TV show, and the Injustice: Gods Among Us video game.