Well, I thought the coolest part from Indiana Jones and the Crystal Skull was where it is revealed that Indy was a double agent for the OSS (precursor to the CIA, see The Good Shepard) during WWII. Now that would have made for a much better movie. As it was, Indy IV was okay, but I think it will be remembered as the 4th best in the series. 
The setup sequence was pretty neat, sort of a tribute to 50's Americana. Now, obviously, what Spielberg and Lucas have always done very well with this series is recreate the feel of old movie-reel cinema cliffhangers (PBS used to replay them on Matinee at the Bijou), where the characters are caricatures and everything is larger than life. This movie is definitely in keeping with that tradition. The foley work was almost comically loud for instance. But surviving a nuclear blast? In reality, if that fridge had been accelerated like that, he would have been turned into goo. And Grays? As Mayan Gods? In a giant flying saucer? Shia as a dead ringer for Marlin Brando in The Wild One? I thought it went too far, but I suppose it's really the only place you can go after immortal crusaders and the holy grail.