- The fight between Evil Superman and Clark Kent... was it all in his head? Was Superman lying on the ground the entire time, screaming and yelling at nothing like a crazy person?
- Possibly. Or the "synthetic Kryptonite" with "tar" in place of the "unknown element" was the movie-verse version of the comics Red Kryptonite, which can do all kinds of wacky things to Kryptonians, including splitting them into two different versions. Depending on how you look at it, Clark/Superman had to fight a battle at the center of the mind to throw off the evil influence of the fake Kryptonite, or it made him evil and eventually split him into Good/Evil halves, and Clark had to literally kill Evil Superman to triumph.
- What exactly is Superman's motivation while being "evil"? Almost immediately after being commended and praised by people, he neglects situations that could use his help, corrects one of humanity's "mistakes" (the Leaning Tower), and (here's the kicker) basically mocks the Olympics, where the world's greatest athletes all come together to compete. He's come to view himself as far above the measly humans he'd previously sworn to protect, to have an inflated ego. This explains why the evil half is represented by Superman, while the good is Clark. It is as an alien visitor with phenomonal powers that he became the selfish idol; it is as the small-town guy with good values that he became the hero.
Headscratchers / Superman III