Reign Of The Supermen was released to general critical acclaim on January 15th 2019. The sequel to 2018's Death Of Superman, both animated movies were shown as a double bill in selected theaters worldwide on the 13th. It was another step in DC/Warner's experimentation with theatrical exhibition for their animated movies, after doing something similar with 2016's Batman: The Killing Joke.
The movie told a story that would have been familiar to fans of the classic '90s comic book storyline, but also included a lot of new elements and other things that fans might have missed upon their first viewing.
Reign Of The Supermen's biggest change to the comic book storyline is installing Darkseid as the villain behind the curtain, pulling Hank Henshaw/Cyborg Superman's strings. The ruler of Apokolips had no part in the original comics, which fans might not remember as the movie does a very good job of ensuring his inclusion makes narrative sense.
It ties the movie into the ongoing DC Animated Movie Universe, following up on plot threads established in 2014's Justice League: War, and continues modern DC's push for Darkseid to be the overarcing antagonist in many of their media adaptations. Some fans might not like that DC have retroactively changed one of their most important stories for an important adaptation, but they executed it extremely well.
Another thing fans of the comics might have missed is that the backstories and motivations for all four imposter Supermen were altered for the movie. Cyborg Superman is reimagined as Darkseid's brainwashed emissary and there is no alliance with Mongol, no destruction of Coast City and no plot to frame the other Supermen.
Superboy is a half-Kryptonian/half-human clone in the movie, with elements of Superman and Lex Luthor's DNA used in his creation; this is his retconned origin which first appeared in 2003, a full 10 years after his debut. Steel teams up with Lois for an investigation into Superman's death and The Eradicator is altered to be a Kyptonian A.I. that can act as a virus -- none of which happens in the comics either.
John Henry Irons, aka Steel, first appeared during the "Reign Of The Supermen" storyline in 1993. A brilliant weapons engineer whose life was saved by Superman, he designed a suit of armor and hammer and took up crimefighting in the wake of the Man Of Steel's death. In the DC Animated Movie Universe, Steel had already made one appearance before the two-part Death and Reign films -- he was in 2015's Justice League: Throne Of Atlantis, voice by The Walking Dead's Khary Payton.
The filmmakers changed the actor this time, however, and fans may have missed that he was actually voiced by someone currently famous for playing a DC character in a live-action TV show: Black Lightning's Cress Williams!
There was another character in Reign Of The Supermen who was voiced by someone already famous for playing an iconic character (sort of) in a live-action DC TV show. Kon-El, aka Superboy, was played with energy and charisma by Cameron Monaghan, who has played the potential Joker characters Jerome and Jeremiah Valeska for the past fews years on Gotham! The two roles really speak to Monaghan's versatility with his voice, as his Superboy sounds nothing at all like Jerome or Jeremiah.
It would've been easy for fans to have no idea until they looked at the closing credits (or found out ahead of time about Monaghan's involvement). He sparks particularly well off Rainn Wilson's vain, verging-on-camp performance as Lex Luthor, and their scenes together are super fun.
This one isn't official as of yet, but there is fan speculation that the President Of The United States shown in Reign Of The Supermen (President Dale) is actually Joan Dale, aka fairly obscure Golden Age character Miss America! In the movie, President Dale seems to be visually modelled after Hillary Clinton, but the role is non-speaking and there isn't any confirmation given about her first name.
It would be a nice easter egg if it was confirmed to be true, and is certainly something only the most hardcore fans are going to pick up on. Miss America was first created by Quality Comics in 1941 and was carried over to DC when they purchased Quality in the '50s. Joan is not to be confused with the two (!) characters bearing the Miss America monicker in the Marvel Universe: Madeline Joyce and the more recent America Chavez.
In Death Of Superman and Reign Of The Supermen the Justice League lineup presented is filled with DC's top-tier characters: Superman, Batman, Wonder Woman, Green Lantern, The Flash, Cyborg and Martian Manhunter. This is a mix of the classic '90s JLA lineup and the New 52 lineup and it's a formidable group of heroes. This animated League is a far cry from the League that existed at the time the comic book storyline came out, which some fans may have missed (or not known about).
At that time the League was a hodgepodge group of lesser heroes, including the likes of Booster Gold, Blue Beetle, Maxima, Fire, Ice and Bloodwynd. We can see why the filmmakers decided to disregard this little quirk of comic book history and give audience's all the big guns.
A crucial plot element of Reign Of The Supermen is the launch of the Justice League Watchtower, their new headquarters. It is depicted as a space station in orbit above the Earth, but in the comics it was originally a building erected in a crater on the moon! Fans might have missed that, in the original comic storyline, the Watchtower did not exist and so its inclusion in the film is a serious deviation from the source material.
The Watchtower debuted in 1997's JLA #4, a full four years after the "Reign" story in 1993, and went on to become a mainstay of Justice League stories in comics, animation and video games. The movie's depiction of the Watchtower is likely influenced by the Justice League Satellite, which was introduced after the original Watchtower was destroyed by Superboy-Prime in JLA #120.
In this day and age, with the ubiquity of superhero content on cinema screens, as well as television shows and animation, it's rare for a character to have never made an appearance. But that is the case with Dabney Donovan, the creepily odd mad scientist tasked by Lex Luthor with cloning Superman in Reign Of The Supermen. Some fans may have believed he was created for the movie, as he's not exactly a household name, but he was actually created by Jack Kirby in 1971 and was the eccentric co-founder of the Cadmus Project!
He once helped Lex Luthor clone himself a new body when he was dying of Kryptonite-induced cancer and later cloned himself after Lex tried to kill him. Cadmus has appeared in countless DC adaptations, but for some reason Donovan has never been included until now.