The 2017 “Crisis on Earth-X” crossover united the Arrowverse yet again, bringing together the CW's Supergirl, Arrow, The Flash, and Legends of Tomorrow. This time, however, they weren't fighting aliens; instead, our heroes had to take down Nazis.
The story focused on a parallel world, Earth-X, where the Nazis won World War II. But what stood out most about this event was how well-oiled a machine it was, in the wake of Warner Bros.' failure to live up to expectations with Justice League. With that said, let's compare the two and see where the Arrowverse event was actually better than Zack Snyder's film and conversely, where it didn't match up to the DC Extended Universe's ensemble movie.
Better: Team Chemistry
The Arrowverse has had years to develop characters from all its shows, even bringing Supergirl into the mix after it came over from CBS. This is why heroes like Flash, Green Arrow, Cisco, and Killer Frost all work so well on-screen with Supergirl, as well as the likes of Firestorm, White Canary, Atom, and so on.
Even with fresher faces like The Ray, Vixen and Isis, the CW knows how to organically link everyone together. This was something Snyder and Whedon failed to achieve, with their team lacking that sense of family that the Arrowverse has in spades, making for better overall team chemistry.
Worse: Lacked Big-Hitters
Reverse Flash told Supergirl that he once defeated Superman, which begs the question: why didn't the CW involve the Man of Steel? It's not like it would turn people away from watching Henry Cavill's depiction on the big screen. The Arrowverse also had Oliver Queen name-dropping Bruce Wayne, so most likely, the Dark Knight exists in this world.
If there is one thing Snyder's universe packs, it's star power - he has access to Superman, Batman, and Wonder Woman, while the Arrowverse is left with mostly minor heroes (Flash notwithstanding).
Better: A Strong Female Presence
The "Earth-X" crossover had a very strong female presence. White Canary, Alex Danvers, Vixen, and Isis combined to take down the Nazis, with non-fighters such as Felicity and Iris also kicking Nazi butt. The driving point of the story, though, focused on Supergirl feuding with her Nazi counterpart, Overgirl.
Justice League, on the other hand, only dealt with two women as part of its major arc: Lois Lane, handling Superman's glorious return, and Wonder Woman, as a key warrior against Steppenwolf. Snyder's film merely treated them like one-dimensional characters, failing to hit the emotional resonance that "Earth-X" did with its ladies.
Worse: Action Sequences
We know television has limitations, but the "Earth-X" action sequences were pretty mediocre. From the fight choreography, which was almost as bad as Iron First, to the poor SFX when Flash fought Reverse Flash, and Supergirl took on Overgirl, the crossover felt like it was on a tight budget.
If it's one thing Snyder's Justice League had, it was spectacle. The fights against the Parademons were awesome, when the League fought Superman it was a thrill-ride, and of course, the final battle against Steppenwolf was quite engaging. The CW, however, needs to take a page from Game of Thrones on how to make television look epic.