I had to listen to this one twice. It's the sort of story where casual comments made by the characters are supposed to clue you in to what is going on.
I think, it's partly about the all gods are/aren't the same comment made at the diner. Is this a different god? An aspect of the same god? I dunno. Personally, I felt this was left vague for a reason. Maybe he was the Anti-Christ?
The character's god was a bit like their families and had come over when the time was ripe and they were able to provide for it.
The narrator didn't know about his religion and wasn't able to tell he was engaging in a ritual to incarnate the god. Victor did. He went to kill the incarnation and was instead inhabited himself. What I felt was an interesting notion was that the interaction between the women and the waitress was a ritual--that it in some way replicated part of the ritual required to incarnate the god. Her eating the pancakes with the apple face of a god was part of the process.
I thought this was also a bit of a shout out to Lovecraft's The Festival with it's reference to a lonely man going back to the place of his ancestors to take part in an ancient festival around a solstice time.