Why does Lex Luthor seem content with just growing ugly rocky crap using the Kryptonian crystals? He does know they are much more than that, part of an alien supercomputer, but the moment that he finds that adding water results in said ugly rocky growts, he forgets about any further researching on what they can do.
He only used one crystal, and saved the others. Possibly he was saving the rest for those later experiments.
Regarding the continent of Kryptonite that Supes chucked into outer space: This thing was sapping his strength like nobody's business while he was carrying it and in fact nearly killed him—how does he know he threw it hard enough? What's to keep it was slinging back however long in the future and taking out a significant chunk of Earth's population?
Well, presumably Superman. He managed to get it off Earth, it's not creating trouble at that moment, and Superman's still around, so presumably he has some time to prepare for that eventuality if indeed it is one. For all we know it ended up smacking straight into Jupiter or something.
While this Troper does love this movie there was till one thing on his mind when watching it. I understand everything else that is debatable such as how Lois Lane had Superman's kid, how he was able to get the mountain off the ground. However what I don't understand is how he was able to survive after nearly dying in the hospital. There was still shards of kryptonite in his wounds (Small, but unreachable.) the stuff on the mountain when it kept growing out gave him enough exposure to kill him. To top it off, it was severely cloudy, the only way Supes could heal would be to fly up like last time and get as close to the sun as possible. Which he couldn't because after throwing the mountain, he fell back into the earth.
Lex's plan for fending off government military intervention against his nascent empire by using "advanced alien technology" is clever, but he's on a seriously tight time budget. He's got to figure out how to produce weapons, shelter, provisions, etc. fairly quickly, because at the moment he's got 3 minions, no weapons beyond a few handguns, and will die of dehydration long before he even gets a chance to starve. His entire operation at its start could be taken over by a single army platoon of green recruits, which the nearest government is likely to do once they realize there's a new continent growing offshore. At the time when he's calmly smoking a cigar and the goons are playing cards, they should be working terribly hard to prepare for the inevitable backlash from the US.
Why is Jason "super?" Assuming we're going by the events in Superman II, before Supes and Lois had sex, he had been transformed by the particle chamber into a normal human being. Did his sperm somehow survive the transformation? And even if it did, wouldn't the remaining "superness" of the developing zygote in Lois's womb have been eliminated when he turned the tables on the villains? Lois was outside with them and exposed to that red Kryptonian sunlight, when he was safe inside the chamber.
The chamber didn't so much turn Clark into a normal human being as it hit him with enough red sunlight to suppress his powers down to normal human levels. He was still Kryptonian, and so were his sperm. And Lois being outside that chamber and exposed to the red sunlight wouldn't have done anything to change the DNA of the fetus developing inside her already.