Deliberate mistake: Although the first account of what happened in Zhao isn't completely true, the arrows penetrating the calligraphy school are sometimes flying at angles that make their trajectory impossible, such as arrows flying perpendicular to the ground or even flying upward.
Deliberate mistake: During the last assault against the hill, a duo of helicopters is mowing down the Vietnamese soldiers with miniguns. In one shot, you can see one chopper coming up behind a tree, all guns blazing. However, the tree, which is in the way of the helicopters right side minigun, remains totally untouched, although, looking at the carnage the guns do to the Vietnamese soldiers, it should have been reduced to toothpicks. (01:51:00)