Question: What did the trooper mean when he said, "Didn't you know this ain't Saturday"? It always makes me wonder.
Answer: I think the trooper makes this joke in reference to Evel Knievel, a popular performer of the day. His shows, which prominently featured motorcycle stunts (particularly jumping) usually occurred on the weekends (i.e. Saturday).
Question: How was Obi-Wan going to become more powerful after he was dead?
Answer: It is heavily implied that one who becomes a Force-Ghost achieves an untold level of power upon entering the state. Given that they have become a pure entity of the Force, it seems to back up the statement. Obi-Wan also becomes free to assist Luke in any case.
In addition to this answer, I think Obi-wan also became powerful because he "let go." He did not feel a need to defeat Vader on this occasion - he was willing to surrender the fight and "move on" to a new state. Something that Vader might not currently understand.
Answer: I agree with Darius Angel's comment. I also think Vader expected a certain sense of satisfaction after defeating his former master. In reality, though, he was still "owned" by the Emperor and was living with the consequences of his choices. Defeating Obi-wan did not change much for him. Obi-wan, however, gained the benefits that Darius Angel mentioned.
Question: In the scene where the American 82nd Airborne is storming the river bank at Nijmegen, there is a brief shot of one of the German defenders, who looks quite startingly like a puberescent boy. Anyone know whether this assumption is correct, and if so, what's the background to this story?
Chosen answer: The Germans did use some Hitler youth movement in the war.
Question: How does the Liparus explode and sink at the end? After the nuclear subs have been destroyed, the ship just starts blowing up for no apparent reason. Was there any explanation for it?
Chosen answer: When the nuclear subs have been destroyed, there's an explosion in the control room, and one of the men cries out "Fuel tank!" Liparus has numerous internal fires raging after the battle with her crew. These uncontrolled fires eventually spread to her fuel tanks and ammo storages, one of which explodes in a huge fireball and finally causes Liparus to sink.
I thought the final explosions that sank the Liparus were deliberate self destruction after completing the mission in an attempt to destroy any evidence, rather like when Bolfeld manually triggers explosives after being thwarted in You Only Live Twice.
Liparus sinks slowly, and that would leave her crew plenty of time to evacuate. Angry and armed crew with a grudge against Stromberg.
Answer: The trooper on the motorcycle had just landed in the water. In older days, the typical day to take a bath, wash hair, etc. was Saturday. The trooper in the car (once he saw the motorcycle trooper was okay and wet) just made a joke about him taking a bath.
Zwn Annwn