Roddy McDowall agreed to be in this film when he heard that they wanted a well-known name in the cast to help sell the movie. McDowall said he'd play a small role for $300 (which he used for car repairs) and filmed his scenes in a day. He also attended the premiere to help generate some publicity.
The film did fairly well at the box office due to the drive-in circuit and audiences hungry for sci-fi films after the success of Star Wars: Episódio IV - Uma Nova Esperança (1977). In the 1980s, Charles Band Productions announced a sequel, tentatively titled "Laserblast 2," about two boy scouts stumbling upon the weapon and terrorizing their hometown. The project was carried over to Band's later studio, Empire Pictures. For years, it was described as in development, partially completed, or fully completed. In the early 1990s, an ad in Variety offered full sale of the film rights, but it's not clear if they were purchased. By the time the film got produced, the original had fallen into obscurity and Empire Pictures had gone bankrupt. The film was reworked to remove the weapon's alien origins, making it a creation of the U.S. military. The end result, Arma Proibida (1989), was written and directed by Michael Miner, co-creator and writer of the original RoboCop: O Policial do Futuro (1987). Band also produced another loose remake, Alien Arsenal, in the 1990s for his Action Xtreme sub-label.
According to the producer Charles Band, the movie was filmed over three weekends for basically no money.
The stop-motion alien models were designed by David Allen and Jon Berg, and constructed by Berg. Although Allen is generally credited with the alien puppet animation, it was largely done by Randall Cook, who worked without credit.
The scene in which Billy blows up a roadside billboard advertising Star Wars: Episódio IV - Uma Nova Esperança (1977) was filmed after principal shooting had wrapped.