Great review! I want someone to talk about this book a Gothic novel. I just feels really gothic to me. Also Jo Walton once said that Gothic novels are about the relationship between a woman and a house. Planetfall is very much about Ren's relationship with her house and also God's City. I also think this feeling is related to what you talked about here with the anxiety.

Also I see a less original YA novel if told form Sung-soo's point of view. It would be a much more conventional story about a teen avenging his parents.