(I've been sitting on this review because I wasn't quite sure where I stood by the end, but I'm going to take a stab at this now.)

The Salt Grows Heavy is a story of identity, changing stories (both positive and negative), fighting greed, trauma, and taking back power. The themes are explored early on in the story as we meet the two main characters: the mermaid and the plague doctor. The writing is quite dense and lyrical, with archaic words that not only add to the dark and fairytail-esque tone of the story but also to the characterization of the mermaid. It might be divisive for readers (especially for those who may find the writing style highfalutin), but I think it fits into the context of the world and the background of the character. For those who do like rich and very descriptive prose, this book is definitely for you.

What gives me pause in giving a higher rating for his book is the way that the themes are handled by the end. Throughout the story, the readers are told about how the mermaid's stories were taken and changed to tame them, using things like love, hope, and purity. I felt that the ending reverted the story to the problem it sought to dismantle at the very start. Other themes like trauma and identity were also not handled well, in my opinion. I thought at first that the root of this issue was the ending, but after sitting on it, I think that there was a lack of buildup that majorly impacted my experience of the ending. The book wasn't able to neatly tie together all of the themes in a way that made the ending cohesive to the whole story or even believable.

Tl;dr: it was a nice story. I would recommend it for specific people who'd like lyrical prose and a dark, fairytail-esque story with two unconventional characters working together. I wish there was a better setup for the ending to tie everything together neatly.