A copy was provided by the publisher through Netgalley in exchange for an honest review 
 The writing in Walking on Knives feels very fairy tale-like. It's much more plot driven than character driven, and quite haunting, in many ways. (As is the original it draws from, which is much more full of despair and rage than the Disney film.) There is some very evocative imagery. It feels as if it's told from far away, which suits the genre. This is emphasized by the fact that characters do not have names, just roles that are used to refer to them. 
 There is an f/f romance at the center of the story. It is presented as such, but I did not believe in it. This may partly be a function of how distant the narrative is from the characters. I did not get why the mermaid would want to be with her love interest, especially given the way this person treats her. I was not rooting for them to be together. 
 I am troubled by what this re-interpretation of the original story does in two core areas: representation of sex work and a disability cure narrative. 
 The story begins with the bargain between the sea witch and the little mermaid not just being for her voice, but also for sex. This particular narrative choice frames the entirety of the story in ways that I am deeply troubled by. At the center, this now feels like a sex work morality tale. (The original does not.) Doing sex work ruins your life, makes you unhappy, places obstacles between lovers, means your love interest will treat you like dirt and the rest of your sex life will pretty much be thwarted. On top of this, the actual sex work scene depicted in the story takes place after the mermaid has given up her voice, and is told in a way that evokes sexual assault; the consent is technically there, but the way it's told feels like it's both physically painful and feels awful to the mermaid. Which reads to me like a story that presents sex work as inherently sexual assault (a common anti sex work framework). Then we come to a scene where the mermaid is attempting to discern why the love interest is helping her, and again there is a sex work type bargain for a kiss, along with being treated very badly. In this scene, the mermaid remembers how terrible it felt to do sex work the first time, in a way that feels very loaded. The sex work drives so much of the story, and it's all presented as negative in a very simple classic way, one that evokes common anti sex work narratives. I found this aspect of the retelling quite harmful. 
 The story also feels like a disability cure narrative to me, particularly around the pain referenced in the title. The mermaid has intense pain while walking, and then is offered something to magically stop the pain, by her love interest. This is a deeply fraught aspect of the story, especially as it then becomes a place of cruelty, bargain, and misunderstanding between the lovers. This is not an incidental cure, but one that drives the plot. I liked that it was not without consequences and strings, as that is often true about cures. But it felt too easy, the way the mermaid handled the aspects of it that were about pain and cure. As a reader who experiences pain from walking and has that as a regular part of my everyday life, it didn't feel like this depiction of it held that experience around cure in a deep or complex way, but instead used it as a plot device, which I found troubling. I gather from comments the author has made that the magical cure shoes were the spark for the story; I really wish that this had gotten more attention in the story and were depicted with more complexity and nuance. I think this is partly a pacing issue and a length issue; the shoes appear so early in the story and much of the story felt like it was rushing along; it doesn't linger the way Andersen's original does. (I would have liked more lingering in general, to be truthful.) 
 In the original story the little mermaid has desire and agency and makes active choices and we get to see that and experience it, even as her choices lead to awful things. In this retelling, we don't really get to see her agency as much, or her desire. We spend much more time on the way others make choices and try to manipulate her, make choices on her behalf. I missed that, missed connecting with the mermaid, missed seeing her take action. There is some action at the very end, but we just see so much reaction for much of the story that the action gets a bit lost. One of the most powerful things about the original Andersen story is the build-up of her yearning and desire. I would have loved to see that here, especially as this is a queer retelling and that feels like such a queer aspect of the original story. 
 Trigger Warnings: (view spoiler)[ The story begins with a depiction of dubious consent/ sexual assault/sex work framed as sexual assault. (It depends on your interpretation; the publisher website refers to it as dubcon, I've seen reviews call it rape, I read it as sex work framed as sexual assault). Sexual coercion. Bad sex that nobody wants to be having described in detail. Relationship with love interest has elements of coercion and stalking. (hide spoiler)]