I have to say, like everyone else, the format is what I found to be the most remarkable aspect of this book. It is written in the format of surveillance footage, IMs, documents, emails, etc. It would be very easy to make this jarring for the reader and lose the plot but that didn't happen at all. I was able to very easily follow what was happening and the different IMs and emails from different people meant we got different perspectives on what was happening. 
 Another issue that could have arisen from using these different formats is that it could lose the opportunity to be descriptive. One of my favourite things about reading is beautiful writing and descriptions which you would think you wouldn't be able to include in an email or message chain because people don't actually talk like narrative is written but the writing was actually just as beautiful as any ordinarily formatted book. 
 The format also made for quite an unreliable narration. Every message and transcription is made by a character, not by an omniscient narrator so you never know what their motives are for writing it. Are they being truthful in that happening? Or are they covering things up, knowing that these files are going to be used as evidence? Having that uncertainty made it all even better. 
 I loved the characters. Each of them were well-rounded and because of the different messages, you could see how they interacted to different people and then how they acted on their own, which was fascinating. I especially liked this with Kady, who was cold and witty to others but sensitive and damaged in her diary entries. I also loved the fact that the characters didn't fit stereotypes - e.g. Kady was a badass hacker heroine and one of the other heroes was a middle-aged overweight computer whizz, which isn't seen that often in YA. 
 The plot was also great. It was filled with suspense and the kind of danger that seems genuinely scary for the reader, not just draw sympathy for the characters from them. You feel like you are right there with Kady and Ezra and everyone else on the ships. I even found myself actually reading every name on the casualty lists because I felt so invested (I found Leigh Bardugo!). The plot twists were brilliant and meaningful and I now do not trust anything that is said in any of these books. 
 Gemina, I'm coming for you.