Just re-read it! :) This is my old review! 
 4.5 
 Can I just take a minute to congratulate the authors on creating such an amazing mindscape? Every page and design and story-telling method was chosen and written in such a way that it enhanced the mood, the seriousness of events, the implications of things, the importance of ideas... I felt like I was a part of the story! Just... wow! Big round of applause! *clapclapclap* 
 This book, despite the sad times and scary moments, was such a fun read! I loved looking at all of the different scenes through different points of view! (my instagram is full of pics of the different formats! @justanotherbookishblog ) 
 So in case you are confused as to what this book is really like, imagine it as a mix between Sci-fi (most of the book), dystopian, and horror. Then, you get a pretty good idea of what Illuminae is like. Artificial intelligence, also known as AIDAN, is almost too smart, too humane. There is a deadly disease that spreads uncontrollable fear amongst passengers. Planets get destroyed. Spaceships break into their atoms. There is a cute love story. 
 ABOUT THAT! Kady and Ezra, the two protagonists, are so awesome! Kady is 18, a computer and hacking genius, and totally awesome, rocking sarcasm and pink hair. Ezra is kind and funny, always wanting to do the right thing, even though it doesn't always show. He's also awesome! 
 AIDAN, the AI unit, is both a 'character' I really love and really hate. It takes over a ship, basically, and attacks another one, but tries to understand human emotion in its own way. This usually leads to and in its system, but it always comes back. 
 ALSO! Am I the only one who read this and imagined AIDAN being voiced by the guy who plays Spock in the recent Star Trek movies?! No? Just me? Okay then, it was worth a try! 
 Now for the story - it was GENIUS! I've been wanting to read a sci-fi like that for a while! Basically, a planet exploded, and evacuating space ships went into space. Kady and Ezra are separated. There is a third ship, an enemy ship. An then from there, the whole thing is like a whole space war! Epic! (I really don't want to give away too much!) 
 The last few pages, where the Illuminae starts talking, left such a cliffhanger that I was kind of in a daze for a while! 
 The only thing I wish could have been different is that it took me up until page 200(ish) to really get into it, and to start understanding the story. 
 I'm giving this a 4.5/5 stars!