Or how I would fix this film with the DCEU:
1- Diana's intro is first and it pretty much starts the movie off. Her intro is the same.
2- Arthur/Aquaman intro is next and it is mostly the same. No mention of the boxes. Bruce tells him that an invasion is coming. Aquaman of course declines Bruce's offer. I would also take out the shot of Aquaman jumping into the ocean backwards and then swimming away because there was no need for it.
3- Victor/Cyborg's intro would come next right after the 2nd scene of Bruce meeting up with Aquaman
4- Steppenwolf invades Themyscira. This would be the 4th scene of course. Would’ve liked if the Amazonian weapons glowed showing that they were magical which would hurt Steppenwolf.
5- Diana visits Bruce. She tells the story of the initial invasion. The Mother Boxes have a different purpose though. These three are special boxes that can’t be transported via boom tube. These three boxes together allow for a bigger boom tube to form, one big enough that it can transport ships or even a planet. Diana explains that Steppenwolf wanted to conquer Earth to harness the power of magic. The Gods fought back and after decided it was too dangerous to keep magic on Earth so they sealed it away. Bruce explains that a recent incident (Suicide Squad tie-in of June/Enchantress) might have caused magic to start slowly returning to Earth.
6- Bruce gets an alert about Barry visiting his dad. Barry's intro happens here and again it's a pretty good scene so I would not change it.
7- Silas Stone is kidnapped by Steppenwolf and parademons. Cyborg starts to hack the internet to find out if there is any chatter on his dad's location. He finds himself in the Batcave computer because he found files about the Mother Box, himself, and the parademons. He talks to Diana since she is there and they meet.
8- Cut to Aquaman saving that sailor. When he brings him back to the bar he notices that he has gills and green blood on him. The sailor wakes up and says that monsters have found out where the box is. Aquaman goes to Atlantis and the scene plays out similar to the one in the movie.
9- Batman recruits Flash and they along with Diana and Victor come back to Gotham. They see the Bat Signal in the sky and go to it. Scene with Jim Gordon is the same.
10- The Justice League goes to where Steppenwolf is interrogating the prisoners. Batman stops everyone from jumping in during the interrogation. They overhear Steppenwolf asking about the boxes and the Kryptonian that of course being Superman. This gets Batman curious. Batman gives Flash the same speech; to save one and then he’ll know what to do. Diana says she can take on Steppenwolf for a few minutes while Batman and Cyborg take care of parademons, and Flash gets the prisoners out.
11- During the battle Steppenwolf's axe breaks the wall. And water starts to slowly leak in. When all the prisoners are out Batman gets into that vehicle and saves Wonder Woman. Steppenwolf attacks the machine and Batman escapes via smoke bomb, a few batarangs, etc. Cyborg comes in and instead of integrating with the vehicle like in the movie he temporarily integrates with the vehicle's weaponry onto himself. The guns now fires lasers instead of bullets since cyborg is now the source of ammo. The League start to gain the upper hand so Steppenwolf opens a boom tube to allow more parademons in. Aquaman who had a change of heart saves the day by bursting in and starts to flood the area even more. He has giant sharks, fish, and sea monsters follow him and start destroying parademons. Aquaman wants the Mother Box back.
12- Steppenwolf sees this as a waste of time and exits. The group meets up and debriefs Silas Stone. He mentions how Steppenwolf kept referring to Superman as if he was weak but alive, and how he wanted superman to go through his “unity process” meaning turning Superman into one of his parademons. This gets everyone thinking Superman may still be alive. They visit his grave and Cyborg scans the body. Superman looks dead but is actually still alive. He is in a state similar to a coma. His heart beats once every few days hence its why the dirt moved in BVS. Cyborg looks through Lex Luthor's notes in the Batcomputer and sees that the Kryptonian ship should be able to heal him.
13- They bring his body and Superman is revived similar to how it was in the movie. Superman is confused and fights them still. I would have the League put up a much better fight though. Aquaman and Wonder Woman should be on a close enough level to where it isn’t a stomp. Batman brings Lois Lane and it ends the same. The Mother Box was activated to bring superman back to life, which is how Steppenwolf was able to know where it is. He takes it uncontested during their fight with superman.
14- Next scene is Bruce hiding that he had his shoulder displaced. The Diana/Bruce scene happens still but without batman being a dick bringing up Steve beforehand. They go back to the team and Bruce mentions that they will coordinate a sneak attack onto Steppenwolf and try and steal the boxes back. Cyborg mentions that the world has gone radio silent. Steppenwolf traveled by ship, but it was not noticed because its purpose is for stealth and breaking communications. Now that he has all three boxes he has started to shut down Earth's communications. Since Cyborg is symbiotic with the Mother Box he can get through and communicate with everyone. The world is in panic.
15- Steppenwolf thinks the world can not unite to stop him like last time. Bruce, however, put a tracking device on Steppenwolf with a Batarang during the Gotham Harbor fight. With Cyborg's help, they can listen in to what Steppenwolf is doing through the tracker, know where he is, and communicate with government officials to coordinate an attack on Steppenwolf. This is where the Justice League officially becomes the Justice League to the government or at least to the rest of the world.
16- Steppenwolf's plan is a two pronged approach. . Dual invasion on two different sides of the planet.
17- Superman scenes at the farm are mainly the same. This would not be taken out and it would be included right in the film right after the 16th scene.
18- Cyborg learns that he has access to the boom tubes, so he transports them onto Steppenwolf's ship while the military tries to coordinate an attack and they try to take out Steppenwolf's base on Earth. The base on Earth is the same location as the one in the movie and we find out it was chosen because it was far away from any fish life. Suicide Squad members cameo in this scene during the Earth attack on the base.
19- The League end up fighting parademons and end up taking them out one by one working together as a unit which leaves Steppenwolf alone by himself having to take on the League all by himself single-handedly. Steppenwolf is stronger now. He is evenly matched with the Justice League and just when he has the upper hand and just as he is about to finish them off Superman arrives and turns the fight around saving the day. I also would not make Superman stronger than Steppenwolf but more even in a 1 on 1 fight. However, all the JL members fight Steppenwolf at once including Superman.
20- Steppenwolf is defeated but escapes Earth through a boom tube. Cyborg then takes control over the ship. He brings back communications on Earth and has the ship block all unwanted boom tube activity into earth. No more sneak invasions from Apokolips without taking down the ship first. We cut to Steppenwolf boom tubing next to where Darkseid is. We see Darkseid for the first time in the DCEU much like how we saw Thanos for the first time in 2012's The Avengers. Darkseid is standing over a bunch of dead Green Lanterns. Darkseid is enraged by Steppenwolf's failure and kills him in one shot of his omega beams.
21- Final scene is of the Justice League all together at their new headquarters which is Steppenwolf's ship which becomes the Justice League's ship since any government that has control, this would be stronger than the other governments of the world. The movie ends with the league looking down on a beautiful shot of the earth and some nice speech.
- Mid credits scene- Green Lantern tease...Guardians of the Universe discuss the invasion of Earth. It is Guardian protocol to promote any planet its own set of lanterns when it is a target of Darkseid. One guardian lambasts on having two more earthling lanterns, saying that three was already enough. We see the rings fly out and we see the Lantern rings find its way to Hal Jordan who finds his ring and John Stewart who finds his ring. Mid credits scene is over.
- Post credits scene- Justice League go their separate ways and Arthur specifically finds his way home where he is met by not only Mera but Vulko as they warn him about Orm but also about impending danger in Atlantis.
