20 Things You Didn't Know About The Omen
19. Richard Donner Had Notes
A lot of religious horror of 70s have moments that are supernatural or ghostly, but when Donner stepped onto the project, he made certain demands to make The Omen stand apart.
Most important to Donner was that the film be grounded in reality. He saw the film less as a work of horror, more of a deconstruction of a family in crisis. So he called on Seltzer to lean heavily on wife Lee Remick's seeming postpartum depression after having Damien (doubled by the doubts that the child is hers).
He also wanted to be able to keep some ambiguity about Thorn's sanity until the end, keeping everything within the realm of possibility.