James Clayton asked Florian Schneider of Kraftwerk at one of their concerts in Canada if he could use François Kevorkian's remix of "Tour de France" and several of their songs in the movie. Florian responded by saying "Yes".
Ex-members Karl Bartos and Wolfgang Flür were also part of the music team on the film.
Seth Green and Sam Simon became the new co-producers and executive producers respectively after the original ones ran off frustrated.
In the opening sequence, Little Girl is seen wearing a dress featuring Little Guy's head with a radio tower on it. The symbol is actually the GreenyWorld Studios' logo.
David Silverman stated that he only worked on the film because he needed to help pay the Film Roman studio building rent.
Most of the money used to make the film were given to the producers by a benefactor.
At one point, Little Girl smacks Little Girl 2 and her pants (and shirt) quickly go down and go back up.
In the director's cut of the film, if you freeze the frame at the right moment, you'll see that the artists actually drew her privates. The director was shocked at the frame, and quickly told the animators to fix that problem. The animators later fixed the mistake by drawing women's underwear (bras and panties) to censor the women's privates. They tested women's underwear on Little Girl 2 to block the privates from being revealed.
The artists who drew clothing for the animated characters, are costume designers and character designers.
The "Reading Rainbow" Sequence is the crossover sequence the animators, artists, and editors had ever made for the film. It contains 2 parts of the sequence:
The first part shows the video clip of the theme song from the Reading Rainbow reboot (2000-2006).
The second part shows a 2D-animated shot of Doctor singing some final words from the lyrics of the Reading Rainbow theme song, while Little Guy shows up and tells Doctor to shut up.
The dances seen in the club scene (where "Whip It" is heard in the film) used Bob Sabiston's Rotoshop software. The dancers used came from New York City and Chicago. One of the dancers was Aleisha Allen, who would later do additional voices for the show.
In the director's cut of the film, it ends with Little Guy saying "No animals, humans, "Ant Humans", and other imaginary creatures were harmed during the making of this film. However, SuperGeo accidentally destroyed a duck", instead of having the message (in text only) at the near end of the film.
Diesel Beanson is Dr. Beanson's imaginary cousin who only appears in the movie as Dr. Beanson's disguise to troll Little Guy. Diesel Beanson looked a lot similar to Dr. Beanson, but he wears different clothing and speaks in a deep voice.
The film was dedicated in memory of Nick Brignola (an American jazz baritone saxophonist and one of James Clayton's musical idols), Arnold Jay (the runner of the GreenyWorld Studios television division and the then-CFO of "Balls" who died in a rail-grade crossing collision during production), Nick Clayton (James Clayton's father who died of lung cancer a week before production of the film began), and Chuck Jones (an American animator best known for his work on the Looney Tunes cartoons who died of heart failure five months before the film's release).
The reason for Little Girl 2 having most of her lines recorded by Denise Oliver in this film was due to Alina Withers' constant trips to therapy. After breaking down in front of the GreenyWorld Studios voice recording crew while recording dialogue for the bicycle-riding scene, she was taken by her former Jeff Jones Show co-star Kristian Michaels to a LGBT therapist, who identified that she was suffering from depression and as a result, Denise, Alina's understudy, ended up recording most of Little Girl 2's lines.
Although Cookie Monster was mentioned in one of the newspapers shown in the film, he actually made an animated cameo appearance as the shopkeeper of Toys R Us. He also made a cameo appearance at the end of the film. His voice was done by David Rudman, one of the Muppet performers for Sesame Street.
His scenes were cut from some versions of the film.
In the director's cut of the film, the post-credits scene originally shows an evil man named "Mango", who attempts to destroy 123 Greeny Phatom, but then decides to check into a hotel and blows up for no reason at all.
When test audiences didn't like it, the director deleted Mango from the film and replace the old post-credits scene with a new one. This post-credits scene shows Green Bob 2 (who is now fully recovered after getting beaten up by Pinky Robot GX), telling the audience to go home and saying "Time for bed!", before vanishing himself with magic dust. It's a lot different than the original post-credits scene, which is cut from the final film.
In the workprint version of the film, after all the credits roll, Little Guy is shown in a room and is seen playing Greeny Phatom: The Video Game on a Game Boy Color, and the camera zooms into the game screen and Little Guy ends up there and and says, "Erook! Erodes!" (Look! Codes!) and then becomes a cheat code.
It was cut due to being considered way too nonsensical by the meddling Fox executives. This scene along with the workprint can be seen on the first DVD release and the 2015 Discotek Media DVD/Blu-Ray/Digital combo by pressing buttons in this order: "Play-Stop-1-2-3-Subtitle-Pause", on the FBI Warning screen or the scene select screens.
This film has many nicknames, including:
Big Lipped Alligator Moment: The Movie
Greeny Phatom The Acid Trip
Felix the Cat: The Movie done by Robert Stainton
Greenypocalypse Now (in relation to taking a long time to get made)
In the British version of the film, some of the lines that are in American English text are replaced by new ones in British text.
New British actors were to record the lines for the British version of the film.