That movie has a lot of foreshadowing in it, so you'll make new discoveries if you watch it again.
The movie has a lot of hints in it to things that happen later, so they'll make more sense if you watch it a second time.
make sense = 意味をなす
hint = ほのめかし
That movie has many sub-plots, so when you watch it again you'll discover new things.
映画の話をすると「伏線」は sub-plot で表現できます。
見返すは watch again か go over/look over になります。
新たな発見は new discoveries です。