Generally credited (along with Indiana Jones and the Temple of Doom (1984)) to influence the MPAA to create the PG-13 rating, as many felt the scenes of violence in both movies were too much for a PG rating, but not enough for an R rating.
The idea for these creatures was born in a loft in Manhattan's garment district that was home to NYU Film School graduate screenwriter Chris Columbus. "By day, it was pleasant enough, but at night, what sounded like a platoon of mice would come out and to hear them skittering around in the blackness was really creepy." Columbus recalls.
Unbeknownst to Joe Dante and Michael Finnell, Steven Spielberg was a big fan of The Howling (1981). After he came across Chris Columbus' writing sample, he fell in love with it and bought it. Then he decided that Dante was the guy to make it into a movie, took the project to Warner Bros. and also produced it with his own company, Amblin Entertainment.
Originally planned and scheduled for a Christmas release, the film was rushed into production shortly after Warner Bros. found out that it had no major competition against Paramount's Indiana Jones and the Temple of Doom (1984) or Columbia's Ghostbusters (1984) for the summer movie season.
Hoyt Axton was always the foremost choice for Rand Peltzer. Pat Harrington Jr. was also considered. Pat Hingle was said to have delivered the best screen test, but was passed on because it was feared Rand's character would take over the picture as a result of Hingle's excellent performance.
Although it is not clearly visible, "Four Magic Moves to Winning Golf", by Joe Dante (senior) is on Billy's nightstand. Joe Dante Junior said his father criticized him for not making the title more visible.
In addition to restoring the classic Warner Brothers logo to the opening of the movie, it was hoped to release the film along with the classic Looney Tunes short, Falling Hare (1943), where Bugs Bunny is harassed by a plane gremlin during WW II. This fell through, but, highlights from the short do appear as part of the Behind the Scenes featurette, that has also been included on the Special Edition DVD.
Little to no actual dialogue for the Gremlins and Mogwai exists in the script in itself. In addition to several instances of on stage rewrites changing or adding to much of the script, the voiceovers were all mostly ad libs, repeating snippets of just performed dialogue or in reaction to other sound effects or environment. To this end, Howie Mandel recorded Gizmo's lines phonetically for foreign dubs of the movie, where localized dialogue and in jokes helped make the picture successful with audiences world wide.
The theater that blows up was subsequently involved in another accident when Marty McFly (Michael J. Fox) in Back to the Future (1985), smashes into the front entrance at the end of the film. The theater then burned down with the rest of the buildings in the fire that happened right after the filming of Back to the Future Part II (1989).
Within the story, Gizmo was capable of singing or humming. Jerry Goldsmith wrote Gizmo's song as well, but Howie Mandel never sang it. A girl member of Goldsmith's congregation was hired to sing Gizmo's song, although she had never worked in films before.
The time machine prop from The Time Machine (1960) can be seen behind Rand Peltzer when he's on the phone with his wife, while attending the convention. A moment later, the machine has disappeared (into the future or the past) to the astonishment of several onlookers. Also attending the convention are Steven Spielberg, Jerry Goldsmith and Robby the Robot
When Billy leads Pete up to his room to show him the Mogwai, a rolled up movie poster for "Twilight Zone: The Movie" can be seen standing on end against a wall. Director Joe Dante directed one of the "episodes" for that film a year earlier.
Zach Galligan revealed in an interview that when the movie was made there was no CGI so all the gremlins were animatronics, each costing USD£30-40,000. So when everyone left the lot for the day security would have everyone pop the trunks on their cars to make sure they weren't stolen.
Gremlins (1984) has several things in common with It's a Wonderful Life (1946) e.g. the two towns have similar names, Kingston Falls and Bedford Falls; Christmas settings; a bank; characters with the name Billy; artwork; George Bailey and Billy Peltzer living with their parents; Murray Futterman's World War 2 stories and the war breaks out during the other film; both Billy and George have a dog; both towns have a heartless miser that try to control everything, Mrs Deagle and Mr Potter; the Baileys run a family business, while Pete Fountaine sells Christmas trees for his father; the door on George's car sticks while Billy's VW is also temperamental; Mrs Deagle hassles the Peltzers while Mr Potter harangues the Baileys; the reporters that try to take George's picture, and Mrs Peltzer taking Gizmo's picture and Kate stunning the Gremlins with a flashcube; Mr Potter and Mrs Deagle both like to foreclose on things; both towns have a bar, Martini's and Dorry's Pub; there are snowploughs in Bedford Falls while Mr Futterman owns one; both George and Billy receive personal calls at the bank; snow in both films; Christmas carols in both films; the broken window at the YMCA and George and Mary breaking the windows of the Granville house; both films have a swimming pool and people/Gremlins fall into them; sheriffs in both films; Christmas cards and It's a Wonderful Life (1946) started as a Christmas card; Mrs Deagle uses a chairlift while Mr Potter is a paraplegic; George feels trapped in Bedford Falls while Kate is trapped in Dorry's Pub; Dorry's packed with Gremlins and Martini's packed with customers; cash registers in both films; both towns have a cinema and a main street; the Gremlin attack takes place on Christmas Eve and the latter half of It's a Wonderful Life (1946) is on Christmas Eve; reporters in both films; Rand's money and the money that Uncle Billy misplaces, etc.
The trivia items below may give away important plot points.
In the script, Murray Futterman was killed during his encounter with the Gremlins but it was changed because the filmmakers found this a little harsh. So, during the news report at the end of the movie (if you listen closely the voice over) you can hear Lew Landers say that he is going to talk with Mr. Futterman at the hospital. In the novelization of the film by George Gipe, this change was not included.
Chris Columbus' script went through a few drafts before a shooting script was finalized. His original version had the creatures killing the dog and cutting off the mom's head and tossing it down the stairs. These elements were never shot due to the fact that both, Joe Dante and Warner Bros. wanted the movie to be more family oriented.
In the original draft of the script, instead of Stripe being a Mogwai who becomes a Gremlin, there was no Stripe the Mogwai and Gizmo was supposed to turn into Stripe the Gremlin. Steven Spielberg overruled this plot element because he felt Gizmo was cute and audiences would want him to be present at all stages of the film. This became stressful for Chris Walas who had designed the Gizmo puppet only for the actions that happened in the first half of the movie.
Mr. Hanson, the science teacher, originally died with dozens of hypodermic needles stuck in his face. But, by request from Steven Spielberg, this scene was re-shot it with just a single needle in the buttocks.
At the end, Gizmo pulls a window blind which exposes Stripe to the sunlight. But, originally, there are two window blinds and Gizmo pull the first one and then Billy pulls the second one. This scene was edited because Steven Spielberg believed that Gizmo was the hero of the movie and not Billy and therefore Gizmo would be the one responsible for the demise of Stripe.