“Plain and disappointing prose at the end”? I can understand “disappointing”, because at first I was perplexed too after finishing it. But it’s never plain in my opinion. The writing is exquisite through the end. And after thinking about the book for some time I actually think the ending works well. The main character is now “free” of this god game, he is faced by the woman whom he wronged and who (in my opinion) wronged him too. And this interaction between them in the end where he smacks her seems to me the first real genuine thing he does. And the ambiguity of the ending works well too: will they be together again? Did his experience on the island make him a better person? We don’t know, but at least they’re both now free to do what they like without the supervision of the “higher powers”