A comment is made about Marvel "not returning our calls." Characters from the Marvel Universe are conspicuously absent from the Lego movies, due to rights issues with Disney. Characters from the Star Wars universe (also owned by Disney) appeared in The Lego Movie (2014), but not in this sequel.

Actress Stephanie Beatriz (Sweet Mayhem) has a signature small scar on her right eyebrow which was caused by, coincidentally enough, tripping on a piece of LEGO when she was 10 years old.

During the "Gotham City Guys" song, references are made to every actor who has played Batman in live action movies since 1966: Christian Bale, Michael Keaton, Ben Affleck, George Clooney, Val Kilmer, and Adam West.

With 13 minutes of end credits, this film currently has the longest amount of end credits for an animated film.

When the Justice League go to fight the alien invaders, someone asks where Batman is, to which Wonder Woman replies that he's off on a solo adventure - presumably, the events of The Lego Batman Movie (2017).

Emmet's Dream House is actually based on the house Emmet crashes through when Lucy gives him the controls to the bike in The Lego Movie (2014).

The LEGO Movie 2 originally had a release date of May 26th, 2017, but was pushed back until 2019 for the spin-off movies.

The opening bars of Everything's Not Awesome has a similar piano and guitar arrangement as Karma Police by Radiohead, hence the reference to the band in the song's lyrics.

Two of the raptors' names are Ripley and Connor. They are named after the two sci-fi heroes Ellen Ripley, from the Alien franchise, and Sarah Connor, from the Terminator franchise.

When Mom steps on a brick, she comments that the level of pain is close to that of childbirth. Obviously, she's joking, but studies have shown that the pain of stepping on Lego bricks is actually higher than that of walking across hot coals or broken glass.

The Man Upstairs doesn't appear on screen except for reused footage from The Lego Movie (2014). Only his voice is heard.

When Rex, Emmet and the raptors arrive at the Sistar System, the scene where they leave the ship is a remake of the scene from Aliens (1986) where the crew rolls out on LV-426 with the same motion detector

Jorma Taccone (voice of 'Larry Poppins') is one third of The Lonely Island who co-wrote and performed the song 'Everything is Awesome' in the first Lego Movie, in collaboration with Tegan and Sara.

Unikitty's brother Puppycorn from the Cartoon Network spin-off series Unikitty! (2017) makes a cameo.

Sweet Mayhem is based on the Lego Friends "mini-dolls".

Richard Ayoade (Ice Cream Cone) and Noel Fielding (Balthazar) are longtime friends and frequent collaborators, having worked together on 'The Mighty Boosh' and 'The IT Crowd', as well as being frequent teammates on 'The Big Fat Quiz of the Year.'

When Emmet makes his spaceship to rescue his friends, he tells Planty to buckle up. This is a reference to "Guardians of the Galaxy", when Star-Lord ( (Chris Pratt)) tells Groot to buckle up.

The movie addresses one of the main criticisms of The Lego Movie (2014), i.e. the fact that even though Wyldstyle (aka Lucy) was the tougher and smarter character and did most of the work, Emmet, the "hapless male", was regarded as the hero.

Three different versions of Wonder Woman are shown on screen; minifig, mini-doll (Lego Friends), and Duplo.

Velma from the Scooby-Doo franchise makes a cameo appearance, possibly to tease Warner Animation Group's upcoming film Scoob (2020).

Jason Momoa does the voice for Aquaman, whom he has played in a series of live action movies.

During the song "Gotham City Guys," the first few notes of Danny Elfman's score for Batman (1989) can be heard. The musical phrase gets remixed repeatedly during his solo.

The LEGO Movie 2 had to be moved to 2019, due also to the two anticipated rival animation films of 2017, Despicable Me 3 (2017) and Cars 3 (2017), both of which are the third installment of their respective franchises, as well as an original film, Captain Underpants: The First Epic Movie (2017).

Rob Schrab was going to make this film his feature directorial debut, until he was replaced by Mike Mitchell.

Cobie Smulders reprises her role of Wonder Woman from The Lego Movie (2014). It was the female superhero's animated theatrical film debut. She was filming Spider-Man: Far from Home (2019) (a sequel to Spider-Man: Homecoming (2017)) around the same time as this production.

Warner Animation Group's 6th feature film.

Before the film was released, it was reported that Gal Gadot was going to play the LEGO Version of her Wonder Woman Character, similar to how Jason Momoa plays his Aquaman Character In LEGO Form, replacing Cobie Smulders from The Lego Movie (2014). This did not happen, for unknown reasons.

The letter R on Rex Dangervest's costume is reminiscent of the R on Batman's partner Robin's outfit.

Will Ferrell, who plays the dad, and Maya Rudolph, who plays the mom, were both cast mates on Saturday Night Live.

The third Warner Animation Group film to be released in February, after The Lego Movie (2014) and The Lego Batman Movie (2017).

Will Ferrell's fourth animated film, after Curious George (2006), Megamind (2010), and The Lego Movie (2014). All of but one of these feature Jonah Hill.

Nick Offerman and Stephanie Beatriz's second animated movie together, after Ice Age: Collision Course (2016), 3 years prior.

This is the first Warner Animation Group's sequel film.

Bruce Willis' fourth theatrically released animated film, after Beavis and Butt-Head Do America (1996), Rugrats Go Wild (2003) and Over the Hedge (2006), as well as his second fully CGI film, with the latter being the first and his first not to be distributed by Paramount Pictures (although the latter film was produced by DreamWorks Animation, it was still distributed by Paramount at the time of release).

The fourth Warner Bros.' animated sequel, after Pokémon the Movie 2000 (1999), Pokémon 3: The Movie (2000) and Happy Feet Two (2011).

The second Warner Animation Group film to be rated PG for mild action and rude humor by the MPAA, after The Lego Movie (2014).

Not counting live-action/animation hybrids like Space Jam (1996), Osmosis Jones (2001), and Looney Tunes: Back in Action (2003), this is the fifth Warner Bros.' animated film to use live-action sequences, after Happy Feet (2006), Happy Feet Two (2011), The Lego Movie (2014) and The Lego Ninjago Movie (2017).

Channing Tatum's fifth animated movie, after The Lego Movie (2014), The Book of Life (2014), The Lego Batman Movie (2017), and Smallfoot (2018).

The second Warner Bros.' computer-animated sequel, after Happy Feet Two (2011).

This is Warner Animation Group's first film to use an opening title, instead of just the logo.

Richard Ayoade's third animated film, after The Boxtrolls (2014) and Early Man (2018).

The Lego Movie (2014) was released the same year as Maleficent (2014). The Lego Movie 2: The Second Part (2019) was released the same year as Maleficent: Mistress of Evil (2019).

Warner Animation Group's first film with a box office bomb.

This is the seventh collaboration between Channing Tatum and Jonah Hill, after 21 Jump Street (2012), This Is the End (2013), The Lego Movie (2014), 22 Jump Street (2014), Hail, Caesar! (2016) and The Lego Batman Movie (2017).

The second Warner Animation Group's musical film, after Smallfoot (2018).

Will Forte's fourth animated film after Cloudy with a Chance of Meatballs (2009), Cloudy with a Chance of Meatballs 2 (2013), and The Lego Movie (2014), all four of which involved Phil Lord and Christopher Miller.

Warner Bros.' seventeenth theatrically released computer-animated film after The Polar Express (2004), The Reef (2006), The Ant Bully (2006), Happy Feet (2006), TMNT (2007), Beowulf (2007), Star Wars: The Clone Wars (2008), Astro Boy (2009), Legend of the Guardians: The Owls of Ga'Hoole (2010), Animals United (2010), Happy Feet Two (2011), The Lego Movie (2014), Storks (2016), The Lego Batman Movie (2017), The Lego Ninjago Movie (2017), and Smallfoot (2018).

The Lego Movie (2014) was released the same year as Godzilla (2014). The Lego Movie 2: The Second Part (2019) was released the same year as Godzilla: King of the Monsters (2019).

The third Warner Animation Group film to use live-action sequences, after The Lego Movie (2014) and The Lego Ninjago Movie (2017).

The second film to feature Mike Mitchell and Mark Mothersbaugh, after Alvin and the Chipmunks: Chipwrecked (2011).

The last Warner Bros.' animated film of 2010s to be rated PG by the MPAA.

Warner Animation Group's last film of the 2010s.

The last Warner Bros.' animated film of 2010s to produced in 2.35:1.

Rex Dangervest's comments about having a chiseled jawline hiding under baby fat are a reference to the physical changes voice actor Chris Pratt went through preparing for his role in Guardians of the Galaxy (2014).

Rex Dangervest (Chris Pratt), the main antagonist, says he is a "galaxy defending archaeologist, cowboy, and raptor trainer". To which Emmet (also Chris Pratt) is confused. These are allusions to Chris Pratt's live-action past roles as Peter Quill/Star-Lord in Guardians of the Galaxy (2014), Josh Farady in The Magnificent Seven (2016), and Owen Grady in Jurassic World (2015).

At the very end of the film, Dad says (off screen), "Honey, where are my pants?". This was the title (and catchphrase) of Emmet's favorite show from The Lego Movie (2014).

During one of the early live action scenes of Finn and Bianca fighting over their Lego, Finn can be heard to say "I'm crafting a narrative involving time travel...", foreshadowing events in the movie.

Rex seems to have some level of meta-awareness as he says to Emmet that everything that's happening isn't real and is just a metaphor for the loss of imagination in the mind of an adolescent.

Near the wedding, Emmet jumps over the rim of the pyramid shaped planet while Rex stays on it while they're talking. This makes it appear as Emmet is standing at a lake talking to its mirror image, which foreshadows that they are different versions of the same person.

This is Chris Pratt's first villain role in a theatrical film.

At one point in the movie, Emmet says "let's go save our friends" to Rex Dangervest, but at this point Rex hasn't met any of them yet. Since the audience have yet to learn that Rex is Emmet from the future, meaning this could be a foreshadowing of that reveal.