Just in case you missed it, an Injustice animated movie is currently in development.
DC Comics and Warner Bros. confirmed as much during a press release for Batman: The Long Halloween, Part Two.
The confirmation was a "blink and you'll miss it kind of moment", so a lot of people didn't notice it at first. Hidden among a list of bonus features for the digital and Blu-ray versions of the upcoming animated film were the words "a Sneak Peek at the next DC Animated Movie - An advanced look at Injustice." Is the Injustice Animated Movie Confirmed? Fans won't have to wait for the unconfirmed sequel to Zack Snyder's Justice League to see what an evil Superman would look like.
Injustice: Gods Among Us was first released back in 2013 by NetherRealm. Famed for their work on the Mortal Kombat games, NetherRealm took their expertise and applied it to a setting where superheroes and villains from the DC universe would duke it out in a fighting game. Although many loved the gameplay and execution, arguably the main draw of Injustice: Gods Among Us was the story mode.
Injustice: Gods Among Us was set in a timeline where Joker successfully tricks Superman into killing his own pregnant, Lois Lane. This, among a series of other events, causes Superman to go mad and become a tyrannical ruler.
Ultimately, this event splits the Justice League, as well as other superheroes and villains, to joining essentially two factions as a result. On one hand, there's Batman and the Insurgency, who are vehemently against Superman's policing of the entire earth. On the other hand, there's Superman and the Regime, who rules the entire world with an iron fist.