The early films of the franchise are infamously accused of being depressingly somber in an attempt to recreate the success of The Dark Knight Trilogy by using the trilogy's superficial aspects without also using its great storytelling, to the point that unfavorable comparisons to The Dark Age of Comic Books were made. This mindset conveniently overlooks how in actuality Warner Bros. just gave the reins to Zack Snyder and writer David Goyer and let them do their thing to start it. Directors that come after Snyder are not obligated to stick with the tone of Man of Steel and Batman v Superman with James Wan only agreeing to direct Aquaman if he was allowed to make it Lighter and Softer. However, since Snyder was responsible for overseeing many of the landmark films like Man of Steel, Batman v Superman and Justice League (until he left the latter's post-production when faced with both studio demands and a family tragedy, resulting in a movie that is maybe 50% from him) the films that would have the most publicity and leave the greatest impact on audiences it's hard for some people to shake the franchise from the tone established in those films. This even contributed to the very negative initial reception to the trailers of the otherwise well-received Titans (2018), as the dark tone drew unwanted comparison to the Snyder films.
Although he gained a cult following thanks to directing Dawn of the Dead to critical acclaim, as well as 300 and Watchmen to overall positive reviews, Zack Snyder became a Scapegoat Creator among many bloggers, Youtube commentators and critics following the mixed to negative reception of his DCEU movies. Many blame him for controversial decisions like including sequences that make no sense to non-comic book fans, setting the tone to be excessively dark, and having Superman and Batman kill despite their traditional and often unspoken rule against it. Of course, many detractors end up overlooking the fact that his works are intended to undergo a Decon-Recon Switch albeit with an admittedly divisive directing approach (although many have stated that they understood what he was going for, but found the execution lacking), and they also frequently overlook some of his accomplishments like his casting of Gal Gadot and Jason Momoa (no one would likely have thought about casting them for the roles of Wonder Woman and Aquaman, and audiences clearly embraced them). Furthermore, Snyder's detractors aren't as quick to blame other parties involved like the WB executives, writers David S. Goyer and Chris Terrio or producer Christopher Nolan, with Nolan himself choosing Snyder as director of Man of Steel and Batman v Superman while also protecting him from Executive Meddling on those films. That having been said, it's still hard to separate Snyder from the franchise's faults, which wasn't helped by his inflammatory statementsnote Some of his statements outside the films have also attracted much anger and scorn, such as claiming in 2008 that Batman could be prison-raped, admitting that he couldn't take superheroes exchanging dialogue while in their costumes seriously and telling people to "wake the fuck up" from their "fucking dream world" where a figure such as Batman wouldn't kill or the fact that the films he did not direct (bar Suicide Squad)note Wonder Woman, Aquaman, and SHAZAM!. were better received.
Jonathan Kent telling Clark that maybe he should have let the kids in the bus crash die, because the world would be afraid of Clark had he revealed his identity. The fact that he doesn't elaborate on why keeping Clark's identity secret is so important doesn't help matters.
The collateral damage caused by Superman during his fights with the Kryptonians and his lack of visible concern for the people caught up in said damage, the latter of which has been frequently brought up as being a stark contrast◊ to everything Superman stands for in his usual depictions.
Infamously, the Thou Shall Not Kill aversion. It is still cited and brought up by DCEU detractors as emblematic of everything they consider to be wrong with the film series, particularly with the lack of prior setup or follow-up.
The use of unsubtle and hamfisted imagery comparing Superman to Jesus in both this film and Batman v Superman has been widely mocked for how on-the-nose it is, as if the audience will not get it unless it is repeated again and again. In this film, Clark ends up in Crucified Hero Shots more than once, and it's quite random so they don't feel like natural pose progressions unlike other examples. He is also literally framed with Jesus in a church's stained glass window. What pushes this from mere Snark Bait to a source of fan ire is the film portraying Superman as a Destructive Savior on top of the Jesus symbolism, making it feel in very poor taste, as well as the fact that it is never used as a means of making an interesting point. The arguments over this pointed out that it additionally feels out of place considering that Superman's creators were Jewish and his foundling origin story has more in common with Moses, that Superman and Jesus are only superficially similar as savior figures, and that this was a Franchise Original Sin of the Reeve movies by casting Jor-El as a God-like father figure, though this film went the extra mile with the Jesus parallels.
Batman and Superman using lethal force (in turn causing their motivations for fighting to be hypocritical, as they hate each other for using lethal force). Special mention goes to Superman crashing a terrorist through several walls at high speed and afterwards claiming that he didn't kill anyone to Lois, which many have brought up as a hypocritical moment for Superman as the terrorist likely wouldn't have survived something like that.
Jimmy Olsen showing up to be murdered did not go over well with the fans as well. Like the aforementioned controversial incident in Man of Steel, the brutal and pointless death of one of Superman's most iconic supporting characters is often used as an example of everything wrong with the DCEU. Not helping is the fact that Snyder stated that it was a means of "having fun" with the character.
The unflatteringportrayal of Mercy Graves hasn't sat well with many fans. Graves went from a badass bodyguard in the cartoons and comics to becoming a generic personal assistant who dies in a bombing orchestrated by Lex. It only got worse when fellow Canon ImmigrantHarley Quinn became a fan-favorite in Suicide Squad while also receiving praise from herco-creators and starring in future spin-offs. Along with the aforementioned Jimmy's death, Mercy's death is often cited as proof that Zack Snyder doesn't respect the Superman mythos.
Superman being unable to find his own mother in Metropolis when he was seemingly able to find Loisa whole continent away in Africa (though it's possible he overheard Jimmy Olsen's distress signal).note leading to the snarky talking point that Superman's heartbeat power only works if he slept with the person he's looking for
The Martha connection in general is seen as too convenient an excuse for Batman to stop hating Superman, especially since Batman was going to straight-up murder Superman in their fight.
Quite a few jokes have been made wondering if Batman has a similarly dramatic reaction every single time he hears the rather common name "Martha."note It should be noted that Batman was still going to kill Superman even after hearing his mother's name and that it wasn't until Lois explained everything that Batman had his freakout.
The entire setup of the battle itself and how it was conducted and resolved were so derided that even Justice League Action and Dark Nights: Metal (ie. the DC Animation department and the COMIC department) made fun of it. As to how bad their passive-aggressiveness is...
One of the best jokes in Teen Titans Go! To the Movies involves Batman and Superman becoming friends after learning that their mothers are both named Martha... and then promptly going back to being at each other's throats after learning that their fathers don't share the same name.
The scene of Wonder Woman watching surveillance footage of the future members of the Justice League (complete with logos for each of them), which is often derided as a very blatant attempt at franchise building, much like the infamous cave sequence from Avengers: Age of Ultron. The fact that Lex apparently decided to create logos for them for no clear reason hasn't helped.
The film's infamously negative reception with both critics and general audiences (as evidenced by its second week drop of a whopping 69% at the box office) is brought up as being indicative of a significant loss of credibility of the DCEU as a whole, which wasn't helped by the similarly-negative reception of Suicide Squad. This ultimately culminated in Justice League, which was supposed to be the DCEU's The Avengers, bombing at the box office.
Related to this, the film's failure to hit a billion dollars despite the insane cost of producing and marketing it and the massive popularity of both Batman and Superman is also frequently mocked.
The continued overly heavy-handed Jesus symbolism from Man of Steel returns, like part of the wreckage in the background of the Doomsday fight looking like crosses, as well as the use of Pietà Plagiarism after Superman dies. Add the fact that in some countries the movie opened on Good Friday (the day commemorating Jesus's death in the [Western] Christian liturgical calendar), and it borders on blasphemy for some audience members.
David Ayer repeating the fans' shouts of "Fuck Marvel!" at the film's premiere. The next day he promptly apologized, saying he got caught up in the moment and has nothing but respect for the MCU crew, but it's still being brought up as a sign of the Fandom Rivalry spilling into the actual creators on DC's side.
The controversial "gangsta" redesign of The Joker is also frequently mocked, with many using it as an example of the supposed faux edginess that the early DCEU films tried to convey. It became pronounced enough that David Ayer eventually owned up to poor reception to the Joker's look on Twitter, admitting that the "Damaged" forehead tattoo was "a step too far."
The heavy, ham-fisted and rushed "course-correcting" operated mid-production on the film definitely didn't sit well with those who were on board with the more serious approach of the previous films, Man of Steel and Batman v Superman especially. It's pretty hard to unsee the aforementioned Uncanny Valley, dodgy humor and overall feeling that the movie has been botched beyond repair as a knee-jerk reaction from executives wanting to address pretty much every criticism of Batman v Superman at the same time without caring about continuity and/or long-term thinking andrelease it on schedule. Then there's all the Missing Trailer Scenes that were chopped, and plenty of Deleted Scenes still on the cutting room floor. This wasn't helped by how the Blu-Ray extras seem to pretend that its Troubled Production never happened.
The gradual revelations that Darkseid was axed from the movie and the fact that he and his subplot were basically replaced by cringy gags and a useless Russian family alienated corners of the fandom that were onboard with the tone of Man of Steel and Batman v Superman (and others who just wanted to finally see DC's equivalent — and the inspiration — of Thanos onscreen) even further in addition to the empty Frankenstein's monster of a film the theatrical film ended up being.
The fact that this version of the movie was rushed even though the executives knew it needed a ton of work. While there are examples of movies being "saved" (like Rogue One) in re-shoots, this movie was not and possibly got worse. There was a rumored test screening that's been said to have gone terribly in February 2017, which would have given them about nine months to change things but the fact that the big cast was involved in other projects around the world and Gal Gadot was pregnant meant that they couldn't get everyone together until that summer to film. Joss Whedon came on board that May which gave them six months to redo roughly half of a movie, a Herculean task by any stretch of the imagination. Reshoots are rumored to have lasted until that September so they really only had two months. The creative team is reported to have asked repeatedly to delay the movie until Spring 2018 but (now ex) CEO Kevin Tsujihara refused to budge. The official cut was only finished a few weeks before release and looked unfinished. In the end, it's a textbook example of how NOT to make a movie business decision.
The film's underwhelming box office run was also an embarrassment. Despite starring some of the most popular superheroes in pop-mythology, the DCEU's answer to The Avengers was a financial bomb that lost at least $50 million. It only became more embarrassing when Aquaman managed to outgross Justice League worldwide in just 3 weeks and actually cross the $1 billion worldwide mark despite starring a hero who is commonly seen by the public as a Joke Character (at least by non-comics readers).