- Actor-Shared Background: Jean-Claude Van Damme's character's last name, French ancestry, and explanation for his thick accent were written into the script after his casting.
- California Doubling: A golf course in Arizona doubled for war-torn Vietnam in the opening scene.
- Divorced Installment: The script for the first film was actually a rejected script for an unproduced Deathlok film.
- Dueling-Stars Movie: It's Jean-Claude Van Damme vs. Dolph Lundgren! It was The Expendables of its time!
- Fake American: Though they're all supposed to be American, the Universal Soldiers are played by a Belgian (Jean-Claude Van Damme), a Swede (Dolph Lundgren), and a German (Ralf Moeller).
- Prop Recycling: The thermal monitors are repainted Cross Changers.
- What Could Have Been: The production script presented a much darker depiction of the U.S. Military than what eventually ends up on the screen. In the screenplay the Colonel in charge of the Unisol project orders Andrew Scott to ruthlessly kill off all the civilian witnesses to his pursuit of Luc Deveraux. The Colonel also informs the head scientist that the terrorists at the dam were not terrorists at all, but mercenaries hired by the army to provide fake justification for the Universal Soldier program. In the finished film, these scenes are omitted so the witnesses are left unharmed and the gunmen killed by the Unisols at the dam were genuine terrorists. The Colonel and his men are actually heroic figures with a real and valid mission who just want their multi-million dollar Unisol back. Whereas military villains were de rigeur in the post Vietnam 1970s and well into the 80s, by the time of filming the reputation of the U.S. Military was at an all time high following the first Gulf War so it was considered unlikely that the audience would accept them being shown in such a poor light.
- Working Title: Crystal Knights.
Trivia / Universal Soldier (1992)