I saw it yesterday and was astounded at the idiotic comments from people walking out of the cinema. "That was way over the top" and "that would never happen".
Indiana Jones has always been a fiction - a fantasy - and an epic one at that. It has never meant to be serious or plausible: every film has its ridiculous parts.
It seems that a lot of people have forgotten that some films are allowed to be overblown and shallow because it's plain fun, and Crystal Skull is exactly that. The stunts, the monsters, the aliens - why not? It's thought by a lot of people that extra-terrestrials came and gave their knowledge to the Mayans and Egyptians.
The ending was fantastically silly - and wonderful for it. This film carried the tradition for what all Indy fims are - overblown and fun comic-book films, requiring you to suspend your disbelief for a couple of hours. It's not the most amazing film ever, far from it, but it was a fun and exhilarating journey.