Freely based on Alexandre Dumas's novel "The Corsican Brothers", as the original working title was. It was even set to take place in France and Corsica.
Ironically, this film and the 1991 action film "Stone Cold" starring Brian Bosworth, were both produced by Michael Douglas's company Stone Group Pictures. Douglas is staunch anti-gun activist. Both films feature heavy gun use.
Director Albert Pyun was briefly approached when the project was then called 'The Corsican Brothers' in the late 1980's. He said on his Facebook page in 2012: "The last time I've spoken with JCVD was on the roof of a building across the street from Cannon on Wilshire. JCVD wanted to talk in private and he told me the story he wanted to do for his next film called "Corsican Brother" which became Double Impact I believe. JCVD asked if I would want to direct it for him. The whole idea of TWO JCVD's seemed a bit far fetched and I did not commit either way but told him I had reservations about how the twins idea would work. I told him I thought he should keep moving in the direction of a pure action star and leave the gimmick movies behind. Haven't seen or talked to him since directly."
When Frank Avery is driving the red sports car back to the house to rescue the family, the shadow of the camera attached to the bonnet/hood are clearly visible on the roadside to the left.
When Chad blows Moon with helicopter kick in last fight, in slow motion we could see that he actually didn't hit him. His foot was at least 12 inches far from Moon's head.