Ray Park was nervous about wearing the ninja suit and asked to practice with it at home so that he could be comfortable with it. He found the suit (composed solely of rubber with a metal visor) like wearing a rubber band, and had to put effort into moving in it.
During the tour of The Pit, Hawk tells new recruits that "knowing is half the battle." The same line was used in public service announcements at the end of the Comandos em Ação (1985) animated series.
The filmmakers enjoyed working with Dennis Quaid so much that screenwriter Stuart Beattie created 10-15 more scenes for him.
Just before the race to the Eiffel Tower, Breaker takes Duke's last piece of bubble gum. This is an homage to the Breaker comic book character, who was often seen chewing, or being reprimanded for chewing gum during missions.
Larry Hama: Hama, the creator of Comandos em Ação (1985), was hired as a creative consultant on the film. He also got a cameo, as a NATO general during the nanomite presentation. The role was cut during editing, and he can only be seen in wide shots of the NATO assembly.
Michael Benyaer: a flight control technician. Benyaer had played Scoop in G.I. Joe: Operation Dragonfire (1989).