This is How You Lose the Time War by Amal El-Mohtar
My rating: 5 of 5 stars
Beautifully written: go read this.
Eloquent, subtle, atmospheric; fast paced but still carrying depth. So much wordplay; if you delight in reading such things, as I do, then you will find the writing itself to be so much joy. TIHYLTTW is what happens when fantasy is used not as a limiter but as a springboard for wild creativity and complexity. (I consider this to be a high tech fantasy; others may feel differently.)
My only complaint as such is I think some of the novel descends into abstract description and I personally would have preferred to dwell on exactly what the limitations of the characters were, if any. That part I found hard to picture. Maybe if this were a novel and not a novella that would be possible; wordcount is a constraint here.
But it is a minor complaint and not nearly enough to stop me loving the book.