Interesting premise, lacking execution

The general premise of this film was pretty interesting. But the final product was flawed, at best. The acting was so stilted in the first act that I could hardly stay with the film. Dr. Gabriel - Ave Maria- how ham-fisted can you get.
The flash-forward to the post-apocalyptic setting - seriously - I think this world was supposed to be a result of the experiments and the birth of David, but not quite sure. Same with the raptured bodies. I think it needed a little more exposition (but too much would have dumbed it down too much.) Was Mr. Cuddles the same as the imaginary friend? Is that why he wasn't raptured? And at the end - we are supposed to assume that was Satan, right? And if the kid's DNA was supposedly harvested from the Shroud of Turin, are we to assume that it was Satan's blood on the shroud? I'm confused by that.
I will say that I thought the boy who played David was the best actor in the film. As was the little girl.
I see this movie as a missed opportunity. Too bad.