After the death of his owner Mr. Wing (Keye Luke), the mogwai Gizmo (voiced by Howie Mandel) becomes the guinea pig of the mad scientists working at Clamp Enterprises, an automatic state-of-the-art office building in Manhattan, run by the eccentric billionaire Daniel Clamp (John Glover). Seemingly at the mercy of the chief researcher Dr. Catheter (Christopher Lee), Gizmo reunites with his friend Billy Peltzer (Zach Galligan) and his fiancee Katie (Phoebe Cates), both who work at Clamp Enterprises. Clamp himself visits and quickly befriends Billy upon being impressed by his skills in concept design, also sparking the interest of Billy's superior Marla Bloodstone (Haviland Morris). Gizmo is left in the office and spawns a new batch of mogwai when he gets wet, including Mohawk (voiced by Frank Welker) who is the reincarnation of Stripe. The new batch eat after midnight and transform into Gremlins.

While Mohawk tortures Gizmo, the other Gremlins cause the fire sprinklers to go off in a cooking show's studio and spawn an army of Gremlins which quickly throw the building into chaos. Billy quickly comes up with an idea to lure the Gremlins outside into sunlight by covering the front of the building in a giant sheet depicting nighttime, Clamp personally escaping outside to lead the plan. The Gremlins invade the laboratory, one devouring a brain serum and becoming the intelligent Brain Gremlin (Tony Randall) who plans to inject a genetic sunblock formula into the army so they can survive in sunlight. Other Gremlins devour serums and are genetically altered, including an electrical Gremlin which Billy traps in Clamp's answering machine. All the while "Grandpa Fred" (Robert Prosky) catches the chaos on camera, broadcasting it to the world; he dreams of being a proper anchorman but only works at Clamp Enterprises as the host of a late night horror show.

Murray Futterman (Dick Miller), Billy's neighbor from Kingston Falls and former victim of the Gremlin's antics, visits New York City with his wife Sheila (Jackie Joseph) and, upon encountering a Gremlin that consumed a bat serum, sneaks into the Clamp building to aid Billy. Billy, Dr. Catheter, and the chief of security Forster (Robert Picardo) team up to defeat the Gremlins, but Dr. Catheter is killed by the electric Gremlin and Forster is chased off by a female lovestruck Gremlin. Mohawk finishes torturing Gizmo and devours a spider serum, transforming into a monstrous half-Gremlin half-spider hybrid. He attacks Kate and Marla, but Gizmo (tired of being bullied by his nemesis) confronts Mohawk and kills him with an ignited bottle of white-out. Outside the building, a rainstorm frustrates Clamp's plan as the Gremlins gather in the building's foyer.

Billy formulates a second plan to kill the Gremlin army: having Mr. Futterman spray the army with water and then releasing the electrical Gremlin, electrocuting and killing all of the army including the Brain Gremlin. Clamp charges in with the police and press, but is so thrilled by the end result that he gives Billy, Katie, Fred and Marla promotions and gives Grandpa Fred a job as an anchorman and gives Mr. Katsuji (Gedde Watanabe) who is a photographer and cameraman a job to be Grandpa Fred's cameraman while Clamp decides to start a new project based on Kingston Falls' tranquil setting from Billy's drawing and hires Billy to design it. Forster calls Clamp where he is trapped inside a restroom in one of the higher levels of the building with the female Gremlin (the only survivor of the army). The female Gremlin approaches Forster in a wedding dress. Forster shrugs and resigns himself to his fate.

• Zach Galligan as Billy Peltzer
• Phoebe Cates as Kate Beringer
• John Glover as Daniel Clamp
• Robert Prosky as Grandpa Fred
• Robert Picardo as Forster, chief of security
• Christopher Lee as Doctor Catheter
• Haviland Morris as Marla Bloodstone
• Dick Miller as Murray Futterman
• Jackie Joseph as Sheila Futterman
• Gedde Watanabe as Mr. Katsuji, a Japanese tourist
• Keye Luke as Mr. Wing, Gizmo's elderly owner
• Kathleen Freeman as Microwave Marge, hostess of a cooking programme
• Twin actors Don Stanton and Dan Stanton as Martin and Lewis, Dr. Catheter's assistants
• Jason Presson (star of Dante's Explorers) as Alex, the Yogurt Jerk
• Belinda Balaski as the mom in the movie theatre
• Paul Bartel as the theatre manager
• Kenneth Tobey as the theatre projectionist
• Hulk Hogan as Himself
• Julia Sweeney as Peggy, the lab receptionist
• Charles S. Haas as Casper, Dr. Catheter's assistant
• Leonard Maltin as Himself

Jerry Goldsmith cameos as a yogurt customer. John Astin cameos as a Janitor. Henry Gibson cameos as an employee that gets fired for smoking. Rick Ducommun cameos as a security guard. Joe Dante cameos as the director of Grandpa Fred's show. Dick Butkus and Bubba Smith cameo as themselves getting attacked at the salad bar.

Voices

• Howie Mandel – Gizmo
• Tony Randall – Brain Gremlin
• Frank Welker – Mohawk
• Jeff Bergman – Bugs Bunny, Daffy Duck, and Porky Pig (Looney Tunes segments)
• Mark Dodson – Daffy Gremlin, Lenny, George, Other Gremlins, TV network announcer
• Kirk Thatcher – Most of the Gremlins
• Neil Ross – Announcer
• Joe Dante – Beanie Gremlin, Witch Gremlin

Along with the main plot, there is animation by Chuck Jones in the film featuring the Looney Tunes characters Bugs Bunny, Daffy Duck and Porky Pig. Jones had actually quit animation before returning to work on Gremlins 2. Dante explained the animation at the beginning of the film was meant to "set the anarchic tone."

The first scene appears at the very beginning of the movie, and features the classic "Looney Tunes" opening card, causing people to assume it is the short cartoon that usually plays before a movie begins; however, when Bugs Bunny appears through the rings on top of the Warner Brothers shield, Daffy interrupts the intro, and steals the shield from Bugs. Daffy attempts to recreate the opening with himself in place of Bugs Bunny, but the shield overshoots, causing the entire title card to fall apart. Daffy surrenders the stardom, claiming that since he won't star in the cartoon, they might as well just skip straight to the movie. Bugs is willing to do so, and spins Daffy off screen like a spinning top for the movie title to appear.

The DVD and Blu-ray includes a longer version of the cartoon short. In it, Daffy is informed by Bugs that he has been promoted to executive and is subsequently put in charge writing the title of the movie. When Daffy mistakenly writes the title Gremlins 2 as "Gremlin Stew", Bugs corrects the error. Daffy then attempts to rename the film The Return of Super-Daffy Meets Gremlins 2 Part 6: The Movie, but Bugs rejects this for being too long, changing it back to Gremlins 2 (rendered in the font of the official logo). Daffy then quits his new job and Bugs decides to add in the subtitle, saying it looks "a little skimpy". This material was removed from the film because early audiences expected a live-action film and were bewildered by the lengthy animated sequence.

The last scene appears after the credits, and again features the Looney Tunes rings. This time, Porky Pig comes out of the rings and says his usual "Th-th-th-that's all, folks!" However, Daffy Duck interrupts again and takes over. After Daffy says the slogan, the back of the Warner Brothers shield smashes him. He peeks his head out to the left side and says, "Fade out," and the segment ends.

The original Gremlins was a financial success, and Warner Bros. asked its director Joe Dante to make a sequel straight away. Dante declined, because he saw Gremlins as having a proper ending, and thus a sequel would only be meant to be profitable. Moreover, the original film was a taxing experience for Dante, and he wanted to move on. Work on Gremlins 2 continued without him, as the studio approached various directors and writers. Storylines considered included sending the gremlins to cities like Las Vegas or even the planet Mars. After these ideas fell through, the studio returned to Dante, who agreed to make the sequel after receiving the rare promise of having complete creative control over the movie; he also received a budget triple that of the original film's. Dante later acknowledged that by this point too much time had passed between the films, thus possibly reducing Gremlins 2's appeal.

Gremlins 2 was shot in New York in June 1989, the film was released in 1990, and as the filmmakers later noted, this was a time when cable television, genetics, and frozen yogurt were becoming more common and influential. This left a mark on Gremlins 2. Gremlins 2 exaggerated what could be seen on cable television at the time, although as the filmmakers noted in 2002, that humour might be lost on present-day audiences. Cable television later grew to provide the same variety. Genetics in 1990 is reflected in the laboratory scene in Gremlins 2, and frozen yogurt is what the mogwai eat after midnight.

Plotting

With more control over the film, Dante engineered a project that he later referred to as "one of the more unconventional studio pictures, ever." Dante included some material that he believed Warner Bros. would not have allowed had they not wanted a sequel to Gremlins. Allowed to break a number of rules in filmmaking, he also later claimed it was the film into which he had put the most of his personal influence. Dante imagined Gremlins 2 as a satire of Gremlins and sequels in general. Another basic description of Gremlins 2 was that, as Dante said, an hour into the film it becomes "extremely cartoony."

The recommended screenwriter, Charlie Haas, brought to the project the basic storyline of moving the gremlins to New York City, and he also imagined a corporate head (the character Clamp) being Billy's boss and at the center of the new disaster. When the Warner Bros. executives grew concerned about the expense of portraying the gremlins attacking an entire city, Haas came up with the idea of confining the action within Daniel Clamp's "smart building". Haas also included a great deal of material in his screenplay that proved too elaborate to produce, including having a cow–hamster hybrid running on a treadmill in the laboratory.

In keeping with Dante's desires to satirize the original film, the sequel has some meta-references and self-referential humor. These include a cameo appearance by film critic Leonard Maltin. He holds up a copy of the original Gremlins home video and denounces it, just as he had in reality; however, his rant is cut short when gremlins pounce on him. Partly for this scene, one academic called Dante "one of contemporary cinema's great pranksters."

Additionally, when Billy is trying to explain the rules regarding the mogwai to staff in the building, the staff find them quite absurd and derisively interrogate Billy on their precise meaning; at one point considering the thought experiment of a mogwai in a plane which crosses a time zone. This scene originates from the fact that the filmmakers themselves saw the rules as irrational, and some questions in the scene were based upon those raised by fans of the original film.

At one point in the film, Dante attempted to involve his audience in the story by making it seem as if the gremlins had taken control of the theatre where Gremlins 2 was showing. The film strip appears to be broken by the gremlins, who then engage in shadow puppetry over a white screen. Professional wrestler Hulk Hogan then appears in a cameo appearance and intimidates the gremlins into running the rest of Gremlins 2. This joke was inspired by a similar stunt in William Castle's film The Tingler (1959). The studio feared that people might leave the theatre if they thought the film had broken; Dante therefore secured the inclusion of the sequence by assembling some people for a preview of the film. When the scene was shown, the real-life audience found it enjoyable and stayed in the theatre. Dante later described this scene as one of the most widely enjoyed jokes in Gremlins 2. When Gremlins 2 made its debut on home video, the filmmakers replaced the scene, to make it seem as if the viewer's VCR had been broken by the gremlins. This time actor John Wayne forces the gremlins into continuing the film, although voice impersonation was needed since Wayne had been dead since 1979; actor Chad Everett was recommended by Wayne's son Patrick Wayne. Notably, a clip from Falling Hare, a film released in 1943 featuring Bugs Bunny and a gremlin, appears in this version. These sequences occur in lieu of the Hulk Hogan sequence which also featured Paul Bartel; home video audiences would not see these sequences until the DVD release (which includes the reworked VHS scene as a bonus feature).

The original version of the film was longer, but executive producer Steven Spielberg claimed that there were too many gremlins, and several scenes were cut as a result. One deleted scene portrayed three of the main gremlins, Daffy, Lenny, and George, sneaking into television host Grandpa Fred's studio and "helping" him host, acting on the premise that Grandpa Fred's show was intended to be scary (though this scene was later included in the tie-in novel).

Casting

Several actors from the original film returned to make Gremlins 2, including Galligan, Cates, and Dick Miller. Miller reprised his role as Billy's neighbor Mr. Futterman, who the gremlins severely injured (both physically and mostly mentally) in the first film, in an expanded role in this film. In the second, he plays a part in wiping out the creatures by turning the hose on them. Character actress Jackie Joseph returned to play Mr. Futterman's wife. Keye Luke also returned to play Mr. Wing, Gizmo's original owner. When Luke heard his character would die in Gremlins 2, he quipped, "Remember, when you make Gremlins 3, I'm a flashback!". Hoyt Axton was meant to return as Billy's father, the inventor. He would have appeared at the end of the film, having designed special clothing for Gizmo that would ensure Gizmo would never come into contact with water again. At the last moment, the filmmakers decided not to shoot the scene to reduce time.

New performers included Robert Picardo, who had previously worked with Dante and producer Michael Finnell in films such as The Howling (1981). He plays Forster, one of Billy's crueler bosses. Robert Prosky played Grandpa Fred, a television host, and his character was based upon Al Lewis's character Grandpa Munster. Joe Dante has a brief cameo as the director of Grandpa Fred's show. John Glover played Clamp (character based upon Donald Trump and Ted Turner) and brought to the role an enthusiastic innocence that overrode the fact that his character had been written as a villain, which Dante thought lightened the film in general.

Christopher Lee (who previously worked with Spielberg in 1941) played the mad scientist Dr. Catheter. Lee imagined his role as light-hearted; but Dante encouraged him to portray the scientist as evil to better match the atmosphere of the laboratory set. Lee was revered on the set for his experience. In a deleted scene, Dr. Catheter examines a bat injected with "genetic sun-block". He then says to his colleague, "I'm told they sometimes feed on blood"; this is a reference to Lee's performances as Count Dracula in the Hammer Horror films. Later, as the Bat Gremlin is transforming, Dr. Catheter experiences Deja-vu (the audience hears Dracula music).

Special effects

For special effects, the original film relied on Chris Walas, who moved on to pursue a directing career. Dante turned to Academy Award-winner Rick Baker to create the effects for Gremlins 2. Baker was not interested, as he saw Gremlins 2 as too much work for a project in which he would not be the creator but rather a successor to Walas. He was eventually persuaded to accept the job when it was suggested he could make the gremlins and mogwai more diverse.

In the first film, when Gizmo multiplied, his off-spring closely resembled himself, except for the leader, Stripe. Here, the four mogwai Gizmo produces each possess their own distinct personalities and physical features. Additionally, each mogwai has a name, although the names were used in the script and never spoken aloud in the film. Two of the mogwais were George, black without a stripe and a caricature of Edward G. Robinson, and Lenny, buck-toothed, named for the principal characters in Of Mice and Men, whom they resemble in both appearance and demeanor. Daffy was named for his manic behaviour, and the leader, Mohawk, for his mohawk hairstyle. Based on the original film's character, Stripe, Frank Welker also voices Mohawk. While both the mogwai and gremlin versions of Stripe had fur stripes, Baker hit upon the idea of giving the Mohawk mogwai a fur stripe and giving the Mohawk gremlin something scalier. Gizmo was also redesigned; the puppet was generally larger and its design was simplified. Dante commented Gizmo may look less real in Gremlins 2, but the result was that Gizmo could convey more emotion.

Later on, when the mogwai evolve into gremlins and multiply, they further diversify by running amok in the bio-lab and ingesting various drugs. One turns into a sunlight-resistant hybrid with a bat, thus becoming the Bat Gremlin. Mohawk becomes part-spider. One becomes part-vegetable (Vegetable Gremlin, as Dante named it), and another consumes a drug and turns into a female gremlin, referred to in at least one script as the "Girl Gremlin" and in the official trading card series and other promotional materials as "Lady Gremlina" with shiny red lips and mascara. Yet another has acid thrown onto his face, quickly presenting a mask of the Phantom of the Opera.

As with the first, puppetry was involved, and some of the puppets were mechanical. An actor holding a puppet would have to have wires strapped to him. Gremlins 2 also includes more stop motion animation than the first film; the Bat Gremlin was portrayed through some stop motion animation. Film technology since the original had improved, and as a result the creatures can be seen walking more. Gizmo is able to dance, although this scene took the longest to make. Because there are more gremlins in Gremlins 2 than the original, additional filming lasted five months. Many of the effects had to be completed after the actors had finished their work.

Music

As with the first film, the music in Gremlins 2 was composed and conducted by Jerry Goldsmith, who also has a cameo in the film alongside his wife. In the latter half of the film, Gizmo, inspired by the Rambo films and tired of the abuse he has suffered at the hands of the gremlins, takes revenge on Mohawk. Gizmo shoots the Mohawk spider-gremlin with a makeshift bow and flaming arrow. For the scene in which Gizmo prepares for this move, Goldsmith – who had also authored the music in the Rambo films – employed a variant of Gizmo's theme in the style of the Rambo theme. The soundtrack was released 31 August 1990 through Varèse Sarabande and features twelve tracks of score at a running time just under forty minutes.

1. "Just You Wait" (2:11)
2. "Gizmo Escapes" (3:43)
3. "Leaky Faucet" (3:45)
4. "Cute..." (1:58)
5. "Pot Luck" (3:00)
6. "The Visitors" (3:31)
7. "Teenage Mutant Gremlins" (3:23)
8. "Keep It Quiet" (3:10)
9. "No Rats" (2:23)
10. "Gremlin Pudding" (2:13)
11. "New Trends" (3:39)
12. "Gremlin Credits" (4:52)

The scene featuring Mohawk transforming into a spider-like monster features a portion of the song "Angel of Death" by thrash metal band Slayer. In another scene, the Brain Gremlin leads hundreds of gremlins to sing Frank Sinatra's "New York, New York". Dante claimed that "The musical number is a shameless steal" from the film Dames (1934).

• Fats Domino – "I'm Ready"
• Jeff Beck – "Sling Shot"
• Jeff Beck – "Situation"
• Slayer – "Angel of Death"
• Johann Sebastian Bach – "Toccata and Fugue in D Minor"
• Tony Randall – "New York, New York"
• Thompson Twins – "Bombers in the Sky"
• Damn Yankees – "Damn Yankees"
• Jasmine Guy – "Tuff Boy"
• Private Life – "Touch Me"
• Gordon Lightfoot – "If You Could Read My Mind"
• Faith No More – "Surprise! You're Dead!"

Film critics varied in their reviews of Gremlins 2, it scored a 68% on Rotten Tomatoes. Roger Ebert, who had approved of the first film, observed that Gremlins 2 was meant to satirize sequels. Nevertheless, he felt it did not manage to differentiate itself from the original enough and was not as good. He went on to claim that the film lacks a well-constructed plot, and once the gremlins arrived the film simply becomes a "series of gags." He thus gave the film two and a half stars, out of a possible four. Hal Hinson of The Washington Post caught on to how the Looney Tunes animation is meant to imply "anarchic wit," but nevertheless felt both the cartoon short and the film itself are failures. He saw the beginning as too slow and, like Ebert, thought the film is too similar to the first. Hinson did, however, approve of the characterization of the gremlins and their version of "New York, New York." He also noted that turning the gremlins against Clamp resembles anti-corporate "poetic justice."

In contrast, while one reviewer for Films in Review, like Ebert, argued the film resembles the original and abandons its plot when the gremlins arrive, he also felt the film's appeal could be found partly in its self-consciousness of these facts and its in-jokes and satire. He also complimented Cates as "wholesomely bewitching," and Galligan as "a suitably naive foil for the scaly fiends." Desson Howe of The Washington Post also approved of the film, including its special effects and the parodies of Trump, Turner, genetics labs, cable television, and the film Marathon Man. Some critics thought the film has qualities the original lacked, such as wit. A critic for National Review called the film "much freer and wittier than the first one," though he felt the sequel shies away from becoming an important piece of satire. The cover of an issue of Entertainment Weekly in July 1990 also exclaimed that "actor John Glover... and director Joe Dante made Gremlins 2 wittier, better, and more subversive than the original." Some critics who found the first film too dark also gave Gremlins 2 more positive reviews. Leonard Maltin, who appears in the film, gave it three out of four stars for its references to other films, Glover's imitation of Turner and Trump, and Lee's performance. An Allmovie critic complimented the sequel by saying the "original's violence and mean-spiritedness are gone, making this follow-up somewhat more kid-friendly." The film was nominated for several Saturn Awards, namely for Best Director, Best Fantasy Film, Best Music, and Best Special Effects. Glover and Picardo were both nominated for the Best Supporting Actor award.

Still, the film did not perform as well at the box office. The trailer introduced the film to audiences by displaying a surface of water intercut with scenes from the original. A narrator goes over the rules regarding how to safely handle mogwai. After the narrator says, "You didn't listen [to the rules]," scenes from the sequel are shown, revealing the gremlins morphing into strange new creatures and then ending with the Brain Gremlin speaking.Gremlins 2 was released into US theatres on June 15, 1990, the same day as Dick Tracy. In its first weekend it made $9,702,804, and it ultimately made $41,482,207. It was thus only the thirty-first highest grossing film of the year, behind a few other films in the comedy, horror or fantasy genre, such as Back to the Future Part III ($87,727,583), Edward Scissorhands ($56,362,352), and Arachnophobia ($53,208,180). It did, however, outperform Predator 2 ($30,669,413), Child's Play 2 ($28,501,605) and The Exorcist III ($26,098,824).

Gremlins 2 also played in other countries. Canadian audiences reportedly enjoyed one scene in which Billy and his boss meet at a Canadian-themed restaurant, where the waiters are dressed like the Royal Canadian Mounted Police. The film was released in Norway on July 5, Finland on July 6, Colombia on July 12, and much of Europe in the rest of July, including in the United Kingdom and Spain on July 27. It opened in France and Argentina in August and reached Australia on September 20. It earned £7,400,000 in the United Kingdom. Later, the film made an additional $20,800,000 in rental stores.

As with the first film, merchandising accompanied Gremlins 2. This may have been integral to the film's purpose. As one critic wrote, "it's a savvy, off-the-wall comedy that acknowledges, yes, it is just one more silly rip-off sequel, produced to sell off the merchandise inspired by the first film." One reference the film makes to the original, an allusion to the merchandising surrounding Gizmo, drew criticism. Some critics saw the mention of merchandise as tasteless. This type of product placement has since become more common.

The new merchandise released alongside the film included PVC figures, plush, and other collectibles by the now-defunct Applause company in 1990. Much later, action figures by the National Entertainment Collectibles Association (NECA Toys) based on characters such as the Brain and Mohawk Gremlins were released. NECA is also releasing mogwais and gremlins from the film in late 2011 and 2012; there will be mogwai and gremlin versions of Daffy, Lenny and George, as well as a mogwai version of Mohawk. The Electric gremlin, flasher gremlin and the Phantom of the Opera gremlin will also be released in action figure form by NECA. There are also newer versions of Gizmo being released, including his Rambo look. Greta, a newer version of Mohawk and Mohawk in Spider form are also being planned for the future.

There were also children's books like Gremlins 2: The New Batch: Movie Storybook, by Michael Teitelbaum, published by Goldencraft in December 1990. Golden Books published Gizmo to Rescue in July 1990. In the United Kingdom, William Heinemann Ltd. had published two tie-in picture books from Buzz Books in August 1990 which contains photographs and scenes taken from the film. They were titled Don't Get Wet and Midnight Feast. Buzz Books had also released other picture books that are particularly sutible for children such as Thomas the Tank Engine & Friends, Fireman Sam, TUGS, The Flintstones, The Animals of Farthing Wood, Looney Tunes, Bugs Bunny, Joshua Jones and Rupert. David Bischoff wrote a novel based on the film published by Avon Books in June 1990. A unique aspect of the novel is how Bischoff adapts the sequence where the film breaks. In the novel, the Brain Gremlin subdues and locks Bischoff in his bathroom before taking the reins for a little bit to explain that the Gremlins take over at this point in the film, his displeasure at Bischoff using the nickname "Mr. Glasses" instead of his official name, and begins a treatise on politics before Bischoff breaks his way out of the bathroom with an axe and subdues the Brain Gremlin. The novel then continues where the film picked up after the film break.

The Spanish company Topo Soft developed a side-scrolling Gremlins 2: The New Batch video game for Amiga, Atari ST, Commodore 64, DOS, MSX, Amstrad CPC and the ZX Spectrum, distributed by Erbe Software in Spain and by Elite abroad, being the first time a Spanish video game company got an exclusive license from a Hollywood movie to make a videogame.Hi-Tech Expressions also released a DOS game at around the same time, but it was poorly received. Sunsoft released versions for the Nintendo Entertainment System and Game Boy in 1990.