I'm still trying to get my head around this book and my thoughts despite finishing it a couple of days ago. I enjoyed the vast majority of the book but I feel as though it didn't quite reach the intended conclusion, it didn't reach its peak. I just felt the twist to be a bit lacklustre which is a shame as it was so promising. 
It explored some really interesting themes and topics with a lot of discourse surrounding race, humanity and gender. However there was also a part towards the end, which I won't spoil, that was super uncomfortable to read and this is probably what I'll remember from this book sadly. 
I'm not sure if I would personally classify this as a horror, but I can see how this book would create a great discussion and I'll definitely be reading others' reviews to see their opinions and takeaways.
2.5 stars