Making it a sequel rather than a new series.
Lex Luthor is the villain...again.
Lex's evil plot is exactly the same as the one in the original.
Supes and Lois look like they should be in high school. Not 5 years older than the characters in part 2.
Supes' face is all weird when he's Supes.
Baby Supes/love triangle.
I only saw the movie once but I know there were other problems I'm forgetting.