Anti-Climax Boss: The majority of the title Dark Knights in the end, as with the exception of Red Death and the Batman Who Laughs, the majority of them are killed off in half a panel.
Awesome Music: The comic has been given its own soundtrack, and as expected with a comic named "Dark Nights: Metal" the soundtrack is made up of amazing heavy metal pieces. "Red Death" a theme for the titular Dark Knight, "Red Death" it's an song so awesome it was even used for the comic book's trailer!
Angst Aversion: It's not uncommon to find readers who are turned off by some of the story elements in this series, which can come across as overly Grimdark to some readers.
Much like DC Rebirth as a whole, this series brings back several characters that haven't been seen for some time and the clear goal with the characters is to act as a celebration of DC's long history. Examples include the Golden Age Hawks, the Outsiders, and Mister Terrific.
After a bunch of alternate universes focusing on an evil Superman, some fans are pleased that DC is balancing it with a story that focuses on a group of evil Batmen from alternate universes instead.
Base-Breaking Character: The Batman Who Laughs was a hit in the Metal event, but he's gotten more contentious with each subsequent appearance, the editorial logic behind it being, Joker and Batman are both popular, right? Let's combine them! More baffling is his lack of resemblance to Bruce... or his stronger resemblance to Judge Dredd mainstay Judge Death...or the fact that The Grim Knight was a more-accurate depiction of how a morals-free Batman would act. (It doesn't help that Joker in an edgy outfit is 90% of what Scott Snyder knows how to write.) Other people thought TBWL was some sort of meta-commentary on the Bat Family. The ethics of having a kid sidekick is clearly something which preoccupies Snyder: TBWL's chained Rabid Robins, his murder of the Bat Family, his breaking of Damian and turning him into dark Robin; all of these seem like a critique of Batman's involvement in the lives of Dick, Jason, Damian, or even Duke and Cassandra. All five had their lives destroyed by outside forces, and many feel Bruce should have just raised them like normal kids—not put them in costumes. Whether that's true or not is subjective, but TBWL is more of a statement than the other demented Dark Knights.
Scott Snyder co-writing has divided fans. While some who liked his Batman run are looking forward to the story, others are disappointed that Snyder is doing another Batman story and want someone else doing this instead. Others, who are Snyder fans, would have preferred he instead write another ongoing and moved on from Batman.
The Immortal Men stuff. Some like that it ties the various immortals of the DCU into each other. Others think it doesn't make sense given the characters' different histories and motivations, and that it's more than a little forced.
Keeping this story separate from the overarching DC RebirthStory Arc and the events of Doomsday Clock especially in light of the numerous similarities the event has with them (focus on The Multiverse and Hypertime, delving in to the nature of metahumans, invoking The Bus Came Back for numerous characters, etc.) On one hand making it separate means the event is generally a more successful take on the intent behind The New 52, where creators could tell new stories with familiar characters without the burden of established continuity, and harkens back to other successful events that were largely one-in-done while having longer term results for the DC Universe. On the other hand not tying it in to the ongoing narrative can be seen as a missed opportunity to reveal answers to some of the mysteries in said narrative, which is especially true of the characters that The Bus Came Back is in effect for.
Catharsis Factor: After establishing himself as a despicable Hate Sink with a Wangst filled origin, fans cheered when The Dawnbreaker got the tar kicked out of him by Hal Jordan even if Hal still ultimately lost.
The Batman Who Laughs is a being born of The Joker's toxins infecting the Bruce Wayne of Earth-22, giving rise to something new and far more evil that slaughtered his entire world. As the right-hand of Barbatos and leader of the Dark Knights, the One Who Laughs gleefully gave all for a chance to massacre entire worlds, summoning Barbatos to Earth to annihilate it and torture and kill everything there. Surviving his master's downfall, the One Who Laughs continues massacring others in his path, tries to start entire world wars, attempts to twist Gotham into pitiless monsters like him, and eventually becomes the herald of Perpetua. Betraying her upon achieving a new cosmic awareness, the One Who Laughs rechristens himself the Darkest Knight, vowing to become a bullet to the Multiverse itself as its worlds fall before him. Slaying Perpetua, he unleashes an army of the worst he has to offer, plotting to turn all existence into a nightmarish reflection of his own soul in an eternal chaos that will devour itself until nothing remains.
The dark god Barbatos, one of the first beings in all creation, turned on and killed his master the Forger, allowing a multiverse of worlds to decay and rot, eventually forming the Dark Multiverse. Influencing Earth to spread evil and cause bloodshed and destruction, Barbatos developed a fixation on Bruce Wayne after encountering him on his trip through time. Barbatos proceeded to allow countless worlds to die to torment each Bruce Wayne and corrupt him in a myriad of realities, choosing the seven most twisted and evil incarnations of Batman as his Dark Knights. Invading the Multiverse and coldly having his loyal servants, the Court of Owls, disposed of, Barbatos has the Dark Knights wreak death and destruction on a global scale, having countless innocents corrupted to serve as a power source for his machines in order to eventually bring the Dark Multiverse into reality, completely wiping out most of the Multiverse and killing or corrupting everything there while Barbatos reigns over it like a god. One of the evilest beings to ever grace the Multiverse, Barbatos shows himself utterly devoted to making everything that lives suffer until it is a reflection of his own twisted self.
Crosses the Line Twice: The Batman Who Laughs killed Wonder Woman by strangling her with her own lasso. It's truly horrifying considering how in many stories Bruce and Diana were close enough to be lovers, but at the same time it's not too hard to see how someone with the Joker's insanity might find it funny.
Evil Is Cool: Of the Dark Knights, many fans just love the designs for the Red Death, The Drowned and the Batman Who Laughs for being cool and different, while still taking enough inspiration to be identifiable as evil counterparts.
Genius Bonus: Starro being able to regrow itself from a small surviving piece makes more sense when you consider his very starfish-like anatomy. Real world starfish have remarkable regenerative abilities, and are able to regrow almost an entirely new body with access to nutrients being the main limitation.
Hilarious in Hindsight: This is not the first time that Batman and metal are in the same sentence together, with Batmetal becoming an internet sensation in Youtube and the Internet just before this book is conceived. Although here, Batman is actually singing to Dethklok songs instead.
Clark carrying Bruce bridal-style, with this look of utter sincerity on his face as he pleads with Bruce to let the League help him, while noting that he knows Bruce's heartbeat almost as well as Lois'.
The Devastator had some... interesting choice of words for his Superman during their final battle.
Devastator: I really...loved you, Clark. I believed in the world you promised us. You made me hope for a better future. But now, I know it was all a lie. And I won't let you hurt me anymore.
Ares didn't kill Wonder Woman in the Merciless' world. He just stunned her, but Batman, under the influence of the helm, killed the god and then her to stop her from taking it off.
The Batman Who Laughs crosses the MEH in the same moment he kills the entire Bat-Family (sans Damian) in order to prevent them from alerting the rest of the heroes about Batman's changes into a "Jokerized" version of him. It only gets worse since then.
The Dawnbreaker crosses it when he murders his world's Jim Gordon just for calling him out on his unnecessarily violent deeds (something he is also implied to have done to his Earth's Harvey Bullock), which is what makes him cross the line from Unscrupulous Hero to a straight-up villain.
The Red Death got his powers by forcibly merging himself with the Flash who is screaming at him to stop while both are ripped apart by the Speed Force. Its also implied Batman murdered all the Rogues to get their tech to fight the Flash.
Metal #2 reveals the last of the metals Batman was investigating has been named after him, Batmanium. In an otherwise harrowing climax, it just kind of kills the moment by how seriously everyone takes the reveal.
The Dawnbreaker's oath, obviously a play on the iconic Green Lantern oath, is awful. It lacks rhythm and is just awkward, and instead of being a moment of awesome, like it's seemingly supposed to be, it's just funny how bad Bruce's poetry is.
The Merciless carving Wonder Woman's likeness into rocks with his fingers. It's supposed to be tragic, but it's just so damn cheesy that you expect a breakup song to start playing over the scene.
Batman's dramatic reveal that he has... a baby Darkseid, and he's not afraid to use it!
Theres only so many times a random villain can pop up out of nowhere, declare theyve made a deal with Barbatos, and then derail the heroes plans before it starts getting comical.
Most people thought the Batman Who Laughs was scary-looking while some fans instead laughed at the character design. He wears what looks like a metal spiked dog collar over his eyes which looks too much like Batzarro's design to be taken seriously. He wears tight restricting leather and heavy Cenobiteish chains which would restrict his moments in combat. He never closes his mouth so his gums look inflamed and puffy and his teeth have filed to points, on top of wearing red lipstick. He looks like a combination of a parody of various 90s Dork Age villains, some kind of concept art for a Hellraiser Batman, and a crossdressing S&M stripper all rolled into one. He also has a bunch of cannibal Jokerized Robins who continuously chant "Crow!" This has earned him the fan nickname "Laughable Bats."
Murder Machine is kind of hard to take seriously knowing that his Start of Darkness essentially boiled down to a grown man old enough to be a father pining for his parental substitute. All the other Dark Knights at least turned bad out of anger or desperation.
The Red Deaths origin: Strapping Barry Allen to the hood of the Batmobile thats been augmented with Cosmic Treadmill tech and then driving it into the Speed Force to merge the two together with Batman standing in the driver seat with arms stretched out like a rock star as both are ripped to pieces. Its both as ridiculous and awesome as it sounds.
The entire series is meant to run on this, as Snyder described his approach as being a celebration of "bonkers storytelling."
One-Scene Wonder: Starro only gets one scene in Issue 4, and is then defeated off-panel in Issue 5. Despite this, the reworking of his character was funny enough to make him an Ensemble Dark Horse.
Some of the Robins cling onto the Batman Who Laughs's leg. Considering his fetish gear look, that imagery is pretty unsettling. Especially since they're numerous Jokerized children.
The Drowned wears an outfit that shows off her sizable bust, but due to her body modifications she's got a nasty case of necrosis around her mouth, with the implication that the rest of her is in a similar state. Presumably her bodice is the only thing keeping her mammaries from succumbing to gravity.
The Hawks' new origin. Instead of the simple idea of a reincarnating Egyptian couple cursed to die forever by a jealous priest, they are now immortals who were killed by an amnesia dagger because of some vast conspiracy. It just feels forced to some as a way to tie every immortal together somehow.
Duke being a metahuman. While he's by no means popular compared to the rest of the Bat-Family, Duke was liked as a more modern take on Robin, as a kid who was normal and was more akin to a partner than a student, one who was very down to the Earth. And now he glows.
The Joker suffers especially hard from this, despite being promoted as an integral part of the story. He only appears in the prologue chapters and promptly disappears from the narrative afterwards. He shows up at the end to help Batman defeat the Batman Who Laughs. Even then, he's a Deus ex Machina.
The Outsiders make their return as an obstensible black-ops team to explore the metals but only get mentioned twice and only seen once, in hologram form at that.
Mister Miracle makes an appearance to help Batman retrieve the Anti-Monitor's dimensional tuning fork and exits the story. Given the New Gods' unique connection with the multiverse it would have been intriguing to see their involvement. Their involvement amounts to their Applied Phlebotinum, Element X, being used as the final weapon used to defeat Barbatos.
Damage is apparently a Cadmus experiment which is connected with similar experiments on others but isn't even seen properly until his own series.
The Silencer gets mentioned but that plot line doesn't come into effect until their titutlar series.
The Immortal Men were aware of the oncoming crisis and are connected to Duke Thomas but don't even appear or get mentioned past the first prologue.
They Wasted a Perfectly Good Plot: There are small hints about the history of the characters that The Bus Came Back for but they're quickly swept aside to deal with the Dark Multiverse invasion plot. Getting more information on the background of these long established characters in the current DC Universe could have been quite intriguing.
The second prologue mentions and shows several immortal characters (Etrigan, Uncle Sam, the Phantom Stranger, Swamp Thing, Ra's al Ghul, etc.) but only a scant few have any bigger role in the story than that.
The ancient tribe plot could have mixed with the immortals sub-plot to go further into the Ancient Conspiracy presented at the beginning of the story.
The Rock of Eternity, Black Adam, and a dagger forged by the wizard which helps move the plot forward all appear but Shazam himself is completely absent.
The Guardians of the Universe were somehow aware of what was going to happen with the Dark Multiverse but the only presence they maintain is Hal Jordan's work during the event which also precludes any further involvement from the cosmic side of the DC Universe.
The Robins that accompany The Batman Who Laughs. It didn't take for artists on Tumblr to produce cutesy fan art.
Unexpected Character: Dream of the Endless from The Sandman shows up at end of the first issue of Metal, and to say it's not expected is an understatement. Not only does he have next to nothing to do with the idea of a mysterious metal connecting to the Dark Multiverse, but he's never been someone who interacts with the wider DC Universe that much. He's also from an old Vertigo comic that was canon with the main DCU, but very unlikely to be canon with the post-Flashpoint DCU. Definitely not one of your predictable appearances.
The third issue brings back Detective Chimp!
Wangst: The Dawnbreaker seems to be Batman's usual angst and brooding taken Up to Eleven, his solo issue having a large focus on how he is "filled with darkness inside" and how he wants everyone to feel as bad as he does. Considering that not only is he a teenage version of Bruce Wayne who had been granted the power of a Green Lantern at an inappropriate time but he's also a personification of one of Batman's greatest fears and regrets, all of this might be intentional.
What an Idiot!: There are several such moments, especially in the Dark Knights' origin stories. Apparently a higher proclivity for murder goes hand in hand with the inability to think things through.
The Batman Who Laughs tries to recruit the other fallen Batmen to his cause at the moment their worlds are being destroyed, promising them that their worlds will be saved and that they will be heroes again. For context, the Batman Who Laughs himself is a Batman who was transformed physically and psychologically to resemble the Joker and plans to destroy the Multiverse, as he has done to his own world. You'd Expect: That given that the Joker is any Batman's worst enemy, they would refuse to join him on the grounds that he is too insane and unpredictable to place their trust in. Or: Since most of them still have some semblance of a moral code, however tainted it may be, they would realize that the Batman Who Laughs's endgame goes against what they believe in and refuse. Instead: They agree to take part in their Jokerized counterpart's plan and buy into his empty promises. Result: Not only does this not solve the problem of their worlds crumbling, but all of the Dark Knights (barring the Batman Who Laughs) get themselves killed during their invasion of Earth-Prime. Even Worse: A couple of the Batmen have their doubts about the plan, particularly the Drowned, who briefly realizes that invading the prime Multiverse for the sake of being a hero isn't a very heroic thing to do, and the Merciless, who dismisses the Batman Who Laughs's statements as lies at first. The Devastator even briefly mistakes the Batman Who Laughs for his world's Joker (for obvious reasons) before agreeing to his deal. And they still follow him throughout the invasion attempt, ignoring their concerns by trying to justify that their actions are for the greater good.
Earth -52 is coming to an end, as all worlds in the Dark Multiverse usually do. The Flash is being pursued by a grieving Batman, who wants to steal his connection to the Speed Force not only to save the world and his fallen sidekicks, but also to overcome the limitation of age. Flash is trying to reason with him so that they can work together to save their world from crumbling. You'd Expect: Batman to listen to common sense and stop battling with the Flash so they can figure something out. Instead: Batman keeps attacking the Flash, eventually succeeding in claiming the Speed Force and killing his rogues gallery with his newfound power. However, Earth -52 is still doomed to die.
When Earth -44's Alfred is killed by Batman's worst enemies, Batman enlists Cyborg to help him create the Alfred Protocol to replace him. However, the AI becomes unstable and murderous, killing every single villain before turning to Wayne Manor, requesting that Bruce "let him in", which Cyborg strongly advises against in favor of shutting it down. You'd Expect: Bruce to listen to Cyborg and deactivate the AI. Instead: Bruce lets the Protocol into the Batcave with hopes of reprogramming it. Result: The Alfred Protocol assimilates Batman, who then embarks on a spree of mass murder before killing the Justice League when they try to stop him.
On Earth -32, moments after a young Bruce Wayne's parents are murdered, he gives chase to the mugger, devoid of any emotion. A Green Lantern ring picks up on his lack of fear and attaches itself to his finger. However, Bruce wants to kill the mugger, which the ring cannot allow. However, Bruce is insistent to the extent that his willpower starts to override the ring. You'd Expect: The Guardians of the Universe to realize that something is wrong with Bruce and strip him of the ring as soon as possible so they can find someone else who is worthy of it. Instead: The ring stays on his finger, allowing Bruce to corrupt it with his lack of emotion. Result: Bruce uses the corrupted ring to kill the mugger, then Gotham's criminals, and the entire Green Lantern Corps when they attempt to intervene.
The Batwoman of Earth -11 loses her lover Sylvester Kyle to rogue metahumans, causing Bryce to seek to avenge his death by killing the ones responsible. You'd Expect: Bryce to simply kill the ones who took Sylvester's life and be done with it, as there are likely many heroic metahumans in her world. Instead: She extends her hatred towards every superpowered individual, eventually killing Aquawoman when she returned from her self-imposed exile. Result: The Atlanteans view this as an act of war, and thus submerge Gotham in retaliation; Bryce is forced to experiment on herself to adapt to these conditions, but she still can't remove all of the water from her city.
On Earth -12, a world in which Batman and Wonder Woman were romantically involved and fought against Ares to prevent him from using a helmet that would amplify his powers by a hundredfold, they succeed in removing the helmet, although Diana has apparently been slain by Ares. Bruce notices the helmet, which Diana warned would corrupt whoever put it on. You'd Expect: Bruce to check for signs of life to verify if she really is dead and make a retreat with the helmet, while also heeding Diana's warnings not to wear it. Instead: Batman assumes she is dead and, driven by grief, puts the helmet on his head to battle Ares. Result: Although he is successful in killing Ares, Bruce is corrupted by the helmet and discovers that Diana was only incapacitated by Ares's attack, but he is so addicted to the helmet's power that he kills her when she tries to take it off.
When his world's Superman went mad for an unknown reason, the Batman of Earth -1 tried to get through to him until Clark killed Lois, his own wife. Luckily, Batman had cultured a modified strain of the Doomsday Virus should he be forced to battle and kill Superman, and the virus can spread from person to person. You'd Expect: Bruce to use the virus as quickly as possible to not only give himself an edge against Superman, but to "inoculate" civilians with it to protect them from the Man of Steel while they are still alive. Instead: Batman only uses the virus in the middle of his climactic battle with Superman. Result: Although Batman succeeds in killing Superman with relative ease, he discovers that there is no one left to save and/or infect with the virus, only a barren expanse of rubble and bony spikes, much to his dismay.
After killing his world's Joker, the Batman of Earth -22 inhaled a dose of his latest toxin, which causes him to adopt Joker-esque mannerisms, as demonstrated when he laughs when Superman tells him that one of the children affected in the Joker incident tore out a psychologist's throat. Both are alarmed. You'd Expect: For either Bruce or Clark to realize that something is very wrong and seek help immediately. Instead: They don't. Result: Batman's condition continues to worsen, culminating in his meeting with the rest of the Bat-Family at the apogee of his infection. He tells them about the toxin's effects on him and admits that he didn't call them over to help him, but to ensure that no one finds out about his condition. You'd Then Expect: The Bat-Family to realize that Bruce is a threat and attempt to restrain Batman as quickly as possible, ensuring that he is in a position where they can help him regardless of if he wants it or not. Instead: They do nothing besides staying where they are. Result: A completely-Jokerized Batman catches them off-guard with a pair of machine guns, killing them before doing the same to the Justice League and the entire world, completing his transformation into The Batman Who Laughs and turn to evil.
Superman. Batman is clearly insane and murdered the entire Justice League and poisoned you. What do you do? Blast him with your heat vision? Use super speed to disarm him? Freeze him with you breath? Do anything other than accept your fate?! Or do you stand there, listen to him monologue and let the kryptonite kill you?
The Woobie: The mainline Bruce Wayne actually manages to lose his drive after finding out his entire life was a lie that Barbatos used to grant him entry into the Multiverse where he could bring about damnation. Not only that, but he was tortured in ways that left him an aged and emaciated husk of his former self.