I picked up Carnivalesque on a recommendation that it's similar to Erin Morganstern's The Night Circus. While they shared a similar setting Carnivalesque fell flat. There's meant to be an air of mystery to the carnival, which I believe is in reference to the inconsistent nature of the carnies and what Dany refers to as something along the lines of a tumble dry setting in his brain.
Jordan stretches this story a bit too thin for it to make sense. It's full of beautiful language, literary references, and interesting characters, but they end up being a façade that doesn't deepen because there isn't enough time to do so within the pages of the book. The plot is concentrated on the first and last 30 pages of the book, and in general I feel like I need a better background in the classic canonical British poets that young boys in the UK learn about to understand the sections by and about Walter and appreciate any literary jokes. The big evil at the end of the book also felt underdeveloped. The reader was told there would be something to fear, but

the dewman's  willingness to kill and desire for the dew we're described in such a way that I felt as disconnected from them in the section about Eileen, which often felt more tangible, as I did in the section about the carnival.

If Neil Jordan ever decided to write a fantasy psychological thriller about Eileen, I would read it in a heartbeats.

The impact of Dany, formerly Andy's, disappearance and the moments in her relationship with the replacement Andy have on her, as well as her public descent into madness is some of the strongest writing in the novel. She is the only tangible character we have as the reader and she, out of all of the characters we're given, is the only one I am able to really find lovable. She loves her son so much that she is able to tell that he's been replaced, and even though she is thought to be crazy at the end of the novel, she's in the right. The fact that Jordan didn't get that same kind of depth in the carnival character gives them an ethereal quality of being unknown to the reader, while the intention seems to be to have them be unknowable to the humans that delighted in their sideshows.

My biggest complaint with the book is Mona and Dany's relationship. She is an ancient being and he's a child. For the first and largest section of the book, Mona discusses him with other characters as being the child she didn't realize she wanted in terms of motherhood, but she kisses him romantically at the end of the novel.

Overall, Carnivalesque was enjoyable. It felt like a fever dream with it's combination of folklore, carnival, and slasher tropes.