Just things I want to throw out:

The eraser dust looks like cremated body
What if Henry's girlfriend was Mary Magdalen of an alien species (he said he didn't know she had a baby, plus her name is Mary X, X being the other species)
He had to kill his baby to die, it was part of him?
Does the bedpost have sexual connotations (girl next door caresses it, Mary X seems to rape it)

Aghh, I don't remember what else. That movie makes you think so much and you just enjoy being lost and uncertain and wondering. At first I wanted less story, but it's really perfect.

Ponder with me, please.