This book was...weird, both the story and the way it was written.

To start with the positives: The narration was excellent. Christine felt very real and human, and her descriptions of the events and her feelings felt genuine. She related things to small moments in her life and to pop culture, and contradicted herself and jumped between the present events, her memories and her perspective from the future. I adored the scene towards the end of the book, where Christine challenges the Horror to a game of rock-paper-scissors, because it also showed how human she was. She used something as small as that game to decide the fate of the world, and woon purely by panicking and not choosing anything, which looked like picking stone, because she kept her fist clenched.
The first person point of view also made me feel more connected to Christine. Describing how the book ended at the beginning was an effective way of making me feel intrigued and wanting to continue.
The references to Bernice Summerfield and Dellah made the story and characters feel part of a wider universe as well, and I enjoyed reading Christine recounting Bernice's family history.

I also enjoyed how meta this book was. Each of the three parts was one of three notebook that Christine was writing in, which she referenced, and she talked about taking a photo of a sphinx that she might stick to the cover of her notebook. That photo she described is the cover image on the original edition of the book!

The twists were genuinely surprising to me and didn't come off as random or illogical. The reveal that Christine was created by Cwej for his ritual was hinted at a couple of times before the end, which means it didn't seem like it came out of nowhere. There were some cool concepts around Cwej's 'employers' (The Time Lords) and their agents. Each regeneration, they evolve and change to be more suited to whatever job they do, was fascinating and weird because it made them seem even more alien. They simply became machines to do what was asked of them.
There were also some interesting dynamics between Christine and Cwej around his separation with humans due to him working for the Time Lords and their genetic altering of him, and if Christine was 'real' because she came from the bottle universe.

However, despite this book being about the end of the world, it felt low-stakes. I think this is because I knew how the book would end (with the end of the world on October 12), so there wasn't a lot of urgency. I also think that Christine didn't attribute much importance to the world ending in her writing, because from her perspective (after these events had happened) she knew that she had only been around on it for a month and left soon after the Time Lords took it over.

I also was confused at points, because of the jumping around, but I imagine I will understand everything properly on a reread.

Overall, I had a really good time reading this. It feels different to other Doctor Who books I've read, and I loved the first-person narration and the weird sci-fi stuff like bottle universes and the Time Lord agents adapting and evolving with each regeneration.