American Ninja (1985)

Continuity mistake: During the first 20 minutes of the movie, Patricia is wearing a pearl necklace. When she is shown sitting in the car, it is a double string of pearls. After she has crashed the car and climbs out, it is a single string of pearls. When she and Joe are running through the jungle, it is once again a double string, and when she returns home it is a single string again. This can not be explained by the necklace being a long string of pearls that's draped twice around her neck, as the necklace is always shown to reach just below her throat, and a longer string would reach further down.

Twotall

Continuity mistake: When Jackson's sitting on his motorcycle talking with Joe he points up with his right hand, which switches to being his left hand in the following shot. (00:34:00)

Continuity mistake: Near the end of the film when the black star ninja and the yank ninja are fighting, they come to a wall with rope hanging down and start to climb.When the camera switches back and forth, you can see that they have both chosen the same rope (they both climb on the rope marked "Gin") even though they are side by side when they climb.

Shinyuki: The Black Star Ninja has betrayed the code.
Joe: Then... he must die.

Shinyuki: These symbols will give your mind ultimate purpose. Gin, Retsu, Zai, Zen.
Joe: Kobudera.
Shinyuki: The Kobudera. Ninja magic. Ninjitsu-to, the ability to seem invisible to cause fear and paralisis in your enemies.

Jackson: Listen to what I'm saying. With your skills, we could make some easy money.
Joe: Jackson, I don't want to fight, I hate crowds, and I don't need money.