Accidental Innuendo: The song "I Just Died In Your Arms" by Cutting Crew accompanies the two scenes in which Batman/Bruce is lovestruck by Barbara Gordon. While the intended joke was probably that 80s music is inherently funny, the song is actually about having an orgasm (title comes from the French expression "a little death"). Basically, this movie was one rating away from having that scene scored to a certain Lonely Islandsong.
Author's Saving Throw: Previous movies such as The Killing Joke faced criticism on Barbara Gordon's characterization, making her The Load whose sole purpose was to be Batman's love interest. This persisted despite their age difference. Here, while Bruce has a crush on Barbara, she makes it clear that while she idolizes him she's not interested in him romantically. She also is a highly competent commissioner who manages to defeat Voldemort.
Award Snub: Much like its predecessor, the film wasn't even nominated for an Academy Award, while The Boss Baby was (though at least it didn't win; Coco beat it to Best Animated Feature). Unlike its predecessor, Lego Batman also failed to get an Annie nomination for best animated feature despite having better critical reception than most of the other nominees.
Awesome Ego: Batman, naturally. He considers this movie a vast improvement on its predecessor simply because it revolves around him, and is constantly bragging about how cool a hero he is. He can't even apologize for kicking Alfred without mentioning his "incredible reflexes".
Broken Base: When it was announced this movie was to come before the true sequel to the first Lego Movie, it naturally split the fanbase. One side was cool with it since Batman was pretty funny in the first movie, making them curious to see a feature film where he isn't so moody. However, the other side was miffed at this, since they wanted Lego Movie 2 first (which got pushed to 2019 due to production on this film and the Ninjago movie), with a good majority of fans likewise complaining about WB cramming more Batman down people's throats.
Creepy Cute: The Joker falls into this, surprisingly enough.
Cry for the Devil: The Joker. Sure, he's evil and has gathered Batman's rogues gallery to wreak havoc upon Gotham, but Batman doesn't consider Joker to be his rival and sees nothing special about the relationship between himself and Joker. Poor Joker looks like he's going to cry after that comment.
Ear Worm: Despite The LEGO Movie depicting Batman as a death-metalhead, the trailers for this movie throw that out in favor of hiphop music... and make it work.
The film's opening song "Who's the (Bat)Man", playing over Batman fighting his entire rogues gallery, also qualifies.
"Friends are Family", the movie's equivalent to "Everything is Awesome", is almost diabolical in its catchiness.
Esoteric Happy Ending: Sure, Batman managed to open his heart and saved the day with his newfound family, but there's still his unresolved issues with Superman and the rest of the Justice League. When word gets out that Batman stole Superman's Phantom Zone projector, destroyed his personal property and almost got all of Gotham destroyed just to save face, Batman will probably be kicked out of the Justice League (and possibly even the Master Builders) for good. But he's also Batman, so...
In The LEGO Movie 2: The Second Part, the Justice League end up heading into space and vanishing for five years, meaning Batman doesn't have to deal with the consequences after all.
Fanfic Fuel: The film is completely lacking the real world element of the original LEGO Movie, leaving it up in the air if this is Finn coming up with another story, or someone else better versed in the Batman lore, maybe someone he knows whom he could collaborate with.
Zach Galifianakis as the Joker delivers a surprising amount of pathos to a villain usually depicted as irredeemable, in addition to having a few moments where he actually sells the character as being intimidating.
Will Arnett as Batman is mostly comedic, but his performance also shines in the emotional scenes, specifically the scene where Batman is trapped in the Phantom Zone and he sees Robin, Barbara and Alfred in danger. His pleads to Phyllis and his discerning voice are genuinely effective.
This is not the only project in which Zach Galifianakis has played a clown.
Remember all that talk about how The LEGO Movie was basically the exact same plot as The Matrix? Well, Agent Smith makes an appearance in Joker's army of Über-Villains.
To promote Batman v Superman: Dawn of Justice, Ben Affleck did a parody video with Jimmy Kimmel and Henry Cavill. When Arnett chimed in by saying that he too has played Batman, Kimmel dismissively told him nobody cares about Lego Batman. The Lego Batman movie ended up getting much better reviews than Dawn of Justice.
Rosario Dawson is a Badass Normal who inspires a group of superpowered people to form a team far stronger than any of them alone. Barbara Gordon, or Claire Temple?
During the credits, Catwoman, Poison Ivy and Harley Quinn are seen walking away together. It has been confirmed that a film adaptation of Gotham City Sirens is being planned as part of the DC Extended Universe.
Batman, as he realizes that Loners Are Freaks and he really doesn't have any friends. It's also worth pointing out that, since it's a Batman tradition, he lost his parents at really young age and the movie clearly points out his less-than-heroic tendencies and desire to be alone all the time are partly a result of his fear of losing people he loves again and is completely terrified when he realizes that his Jerkass attitude almost led people he cares about the most to their doom and that Robin almost went down the same path.
The Joker. He may be insane, but is legitimately heartbroken that Batman doesn't think of him as his greatest enemy.
Dick Grayson is just downright adorable with his cheerful nature, helped by Michael Cera doing his voice.
Harley Quinn, her curly pigtails and clown/goth outfit for whatever reason makes her adorable.
Shockingly, the Joker of all characters delves into this at times, albeit in a Creepy Cute way.
Nightmare Retardant: The information we get about Gotham City being built on two tectonic plates above an empty abyss may be terrifying to the characters, but to the audience it's hilariously clear that they're talking about a tabletop set.
Older Than They Think: The age gap between Dick Grayson and Barbara Gordon. In most media appearances, the two are depicted as being around the same age, and in a relationship. Their age range portrayed here is actually much closer to the original portrayal from the Silver Age of Comics When originally introduced, Barbara Gordon was a good 8 years older than Dick, and well into her career. It was until much later in the comics run that Barbara's age got retconned to being closer to Dick's.
One-Scene Wonder: Pretty much the best any character and Batman villain not named the Joker or Harley Quinn can hope for in this movie. Some of the notable ones:
Despite being heavily shown in marketing, the majority of Batman's rogues gallery, in this case everyone except Joker, is reduced to being minor rolesat best, due to the Joker recruiting villains from other LEGO properties instead. It also doesn't help that they used the entire rogues gallery, including lots of the silly one-off ones, so there's really no time to give them all attention. The most notable example of all is Two-Face. Billy Dee Williams finally gets to play Two-Face after being introduced as Harvey Dent in the 1989 movie... and he only has two lines and doesn't get much screentime.
Many, both fan and pro are further a bit off-put that the villains from other media franchises recruited from the Phantom Zone are used in such generic ways that one could completely swap the characters out and replace them with almost any other baddy without changing one iota of anything that happens, making it uncomfortably similar to the trend in modern spoof films where merely citing such characters exist is treated as funny in itself. The most notable exceptions to this are Sauron, who plays a crucial part in detecting the Bat-Family's movements and needs to be taken out in order for them to gain an advantage, Lord Voldemort, who serves at the Joker's right hand along with Harley and is constantly casting magic spells (all of them at JK Rowling's own suggestion!), and the shark from Jaws, whose presence revolves entirely around the fact that he is a shark and makes the Bat Shark Repellent Chekhov's Gun joke work.
Any character that is not a member of the Bat-Family, The Joker, or a Guest Fighter. The Justice League only appears once in a party scene and none of them do any superheroing.
We are introduced to the Phantom Zone with Superman telling us he sent General Zod there. Yet Zod is only visible as an extra among Joker's Phantom Zone villains.
Some people feel put off that Harley plays a minor role besides freeing the Joker and his new posse from the Phantom Zone. It doesn't help that Jenny Slate voiced her, which would normally seem like a great casting choice.
Also, in a case of They Wasted A Perfectly Good Tie-In Opportunity, one would think that a multi-platform video game based on the movie by Traveller's Tales is guaranteed. Instead, it gets a game released on mobile phones, and a Story Pack in LEGO Dimensions. Though considering Batman had a Lego game way before this movie came out (Heck three of them at the time) as well as a DTV movie based on said game. It's likely they wanted to avoid confusion.
Tough Act to Follow: While consensus among critics is that this movie is a very entertaining film, they didn't think it was quite as good as The Lego Movie, and its box-office tallies seem pretty low compared to those of TLM, especially domestically.note The Lego Movie: $258M domestically, $469M worldwide. The Lego Batman Movie: $176M domestically, $310M worldwide.
Trailer Joke Decay: Batman explaining why the Batwing only has one seat, though mitigated a bit by the scene in the film having the extra wrinkle that he just built the plane and knew full well he'd have company in it.
There's also the scene where Batman is microwaving a lobster. Being quiet and drawn-out is funny on its own, but when it's advertised repeatedly the release just makes it seem like a premature intermission.
Ugly Cute: The Joker may have jagged shark teeth but he's still a cute little lego piece.
The film features LEGO versions of the Kabuki Twins from The Batman, Penguin's enforcers who had never before appeared outside of said show. The film also includes a good number of relatively obscure Batman villains, like King Tut, Crazy Quilt, the Mutant Leader, and even Polka Dot Man. It gets lampshaded; after Joker lists off a number of obscure villains, the person he's talking to asks if he's making some of the names up. He responds that he isn't, and tells them that it's "probably worth a Google."
Among the rosters of the Justice League are almost all the original characters created for Super Friends (El Dorado, Samurai, Apache Chief, Black Vulcan, the Wonder Twins and Gleek, with Wonder Dog DJing the party).
The Woobie: Dick. The poor boy is an orphan who's desperate to be adopted and wants nothing more than a family of his own. Batman treats him initially during the movie as an expendable sidekick who he originally uses simply for a mission that was too dangerous for him to go on by himself, with the young protege going along with it happily unaware Batman is basically sending him off to a potential death. Fortunately, he immediately impresses Bats with his own badassery.