1. you let go of everything (giving up his last life boat) and you will find god (the person that saves him).
Mark 8:35
"For whoever wishes to save his life will lose it, but whoever loses his life for My sake and the gospel's will save it.
2. All the 'amen' lyrics in the ending song.
3. director is a born again christian
4. the hand saving him is coming out of a bright light symbolizing god and salvation
I didn't see it as an overtly Christian film, like the Kirk Cameron movies, but yes, it does have religious imagery as you pointed out.
Using Biblical imagery doesn't necessarily make a movie 'Christian', but it does enhance the underlying theme of a movie if done in the right way. Cool Hand Luke for instance does a wonderful job in using such imagery. In college I was told that the Bible should be on everyone's bookshelf. If not for your faith, it is referenced in scads of literary works and you should at least be familiar with it.
"Loves turned to lust and bloods turned to dust in my heart"