Re: Flashbacks, or straight forward storytelling?
Something like that. I could see the first act ending with Jor-El in the FOS telling Clark about his past, showing some great scenes from Krypton. And then possibly opening the second act with Zod and co approaching earth.
I think the movie might open with a quick intense glimpse of a partially destroyed Krypton.
"Anyone who has never made a mistake has never tried anything new"