Continuity mistake: During the ants scene, Indy is about to grab a stick to the left of his hat. In the close-up the stick and the hat have swapped sides.
Continuity mistake: While Mutt's bike is sliding along the library floor, right before it comes to a stop it's pushing a chair on the right. A frame later the chair has magically made a 180ยบ turn and moved half a meter to the right.
Continuity mistake: When Col. Spalko begins cutting the leather covering the alien corpse in the casket, no straps are seen. In the close-up shot a strap is suddenly visible.
Continuity mistake: In the race between the soldiers and the youngsters in the roadsters, there is a shot of boots on the military vehicle's pedals and the next shot is of sneakers on the same pedals.
Chosen answer: Because the film had a global release date, and premiered the same day in every country in the world. Obviously, the studio felt this was the best day to do it.
Twotall