Superman is a pretty faithful adaptation of Big Blue, with one major exception – Clark Kent's biological father Jor-El is revealed to have a sinister agenda for planet Earth.
As revealed midway through the movie, after Lex Luthor gets his hands on a holographic message from Jor-El and Lara-El that accompanied Clark to Earth, it turns out that Jor-El sent his son to subjugate the planet and its people, completely unbeknownst to Clark himself. Usually, Jor-El's mission is the complete opposite.
