Question: The Soviets are led to the temple by a trail of dropped "bleepers". Is this a reference to the trail of M&Ms that Elliot leaves for ET in "ET"?
Rlvlk
Question: When they are in the Soviet jungle camp, Indy is shown an alien whose skull is crystal on an 'operating table.' But I thought the last crystal skull was in the bag the Soviets were holding onto. If that's the case, then they had two crystal skulls, not one, right?
Answer: They had at least one skull (and body) from the spaceship crash in Roswell, but they needed a specific skull - the one from one of the original alien visitors.
Answer: Doubtful. Dropping breadcrumbs was in in Hansel & Gretel. The breadcrumbs here are just fancier.
Rlvlk