This is the only entry in the series to star both actors that portrayed the American Ninja in previous films (Michael Dudikoff of American Ninja 1 & 2 and David Bradley of American Ninja 3).
David Bradley claims that he had lobbied the producers to have his and Michael Dudikoff's characters work in tandem throughout the film, but his efforts were frustrated when Dudikoff agreed to appear only on the condition that his character would save the day on his own, and clearly be shown to be the superior fighter.
In the first scene when Michael Dudikoff appears, he is teaching a group of children in a church, as he starts the class, he writes "environment" in the board and reads it out loud, but he reads "en-vi-OR-ment" when it should be "en-vi-ROn-ment".
In the opening scene, as the Delta Force commandos hear the sound of one of their comrades screaming, a crew member's lap (wearing jeans) is perfectly visible in the bottom left-hand corner of the screen.
When Joe fights the ninja in the boiler room (right before the from-below-shot of him climbing the stairs), he throws a punch at the ninja's head, and there is a loud punching sound effect accompanying it, but a close look reveals his fist stops a foot in front of the ninja's face.
What are the differences between the BBFC-18 VHS and the uncut version?
A
Three scenes were cut due to the usage of martial arts weapons. As of today (Dec. 2009) no uncut version is available in Britain. A detailed comparison with pictures can be found here.