The view of the "city lights" is a model which includes a suburb that looks suspiciously like a circuit diagram, complete with logic gates and an integrated circuit.
When the helicopter pilot looks the newspaper, one of the headlines says "Kingston Falls 'Riot' Still Unexplained". Kingston Falls was the town where the events in Gremlins (also directed by Joe Dante), took place.
Cherie Currie was considered for a part but, according to her autobiography, she was in the throes of drug dependency and couldn't even make it to a meeting.
The computer Wolfgang uses to control the bubble and eventually the completed spacecraft is an Apple IIc, a computer released by Apple in April 1984 that sported a blazingly fast 1.4MHz processor and 128 kilobytes of RAM.
The film was never finished, and was released as a work in progress when the studio decided to move up the release date and release the film as it was, telling director Joe Dante that he was finished and they were going to go ahead and release what he had at that point.
The ranting and raving of Wak and Neek's Dad is peppered with just barely recognizable bits of English including "You have no respect for authority!" and "Wolfgang? Who the hell is Wolfgang?"
Wolfgang's "talking" rat is named Heinlein, after science fiction author Robert A. Heinlein, who wrote many stories about young boys experimenting with spaceflight.
At one point, the boys are watching at the Drive-In a movie featuring a spacefaring hero named Starkiller. George Lucas originally intended the lead character of his movie Star Wars: Episode IV - A New Hope to be called Luke Starkiller until he changed it to Skywalker at the last minute.
One of the movies that Ben watches is This Island Earth. In that movie and this one, the character builds a device with help from an alien so that they may meet.
The two "deleted scenes" on the DVD were part of the original theatric release, accounting for its longer playing time, 109 minutes compared to 106:25 for the DVD feature.
River Phoenix, who had grown up in communes in South America, was somewhat unfamiliar with popular culture and slang words. During rehearsals it became a running joke when he would attempt scripted well-known words and phrases and usually pronounce them incorrectly.
There are numerous references to Looney Tunes cartoons throughout. When the boys create the sphere in Wolfgang's basement and it goes crashing out a window, the imprint in the glass looks suspiciously like Bugs Bunny's head. Also, Wak's first words to Ben and Darren are "What's up Doc?".
Wak can be heard uttering a line of dialogue from The Maltese Falcon in response to Darren's question about the crystal gift given at the end of the film. The line is "The uhh... stuff that dreams are made of."
When Robert Picardo was in full makeup and costume as Wak, his mouth was the only part of him not completely covered (though his mouth was made up to blend in with Wak's face).
During the children's flight over the circuit board at the end of the film, some of the camera angles and moves are meant to mimic the flight to Neverland from Disney's Peter Pan.
Originally the film was going to be directed by Wolfgang Petersen, who wanted to film it in Germany. The studio balked at this decision. Petersen would go on to direct 'Enemy Mine (1985)', which was filmed in Germany and released by Fox later that year.