Re: Shouldn't Zod have manhandled Supes?
I've got two explanations. But they would both be up to the individual to decide whether they are worthy explanations.
1. Superman (like Jor El in the beginning of the film) was fighting for his family. He was fighting to save Earth. Including Martha, Lois and the entire race of people who raised him. This gave him the extra push he needed to defeat insurmountable odds.
2. General Zod was on a self-destructive, even suicidal path after he lost his own family/people. He wanted Superman to kill him. He even stated Kal took away his reason for existing.