The other things I'm noticing are very much to do with now knowing the partly-twist, partly just ambiguous ending:

• Some of it sure reads different now that I know the narrator is causing the odd feeling in Fetter's gut that leads him in fruitful directions.

• He is so very adrift for most of the book, even with his shadow pushing him this way and that. If anything the ending feels more ambiguous now, with that knowledge that the shadow did some orchestrating, without being able to tell how much of a grand plan it ever had.