UPDATE 
 I actually don't have anything to add... So, I'll just elaborate the reasons behind why this book is amazing (or at least for me) 
 1. THE FORMAT. Well, if you've read Illuminae before, you'd be familiar with the amazing format. I love the format so so so much. The format makes me feel like I'm part of the story. I'm one of the investigator of the case presented in the files. Also, it's fun how you will never know what the next page would look like. It could be a chatlog, email, messenger, drawings, phamplet, etc. 
 2. THE ROLLERCOASTER PLOT 
 I just... I don't know.... Amie & Jay are the master of trolling people. seriously. The plot is so intense! It's one hell of a ride. It was so intense until I screamed out of disbelieve of what was just happened. I need to stop reading at one point just because I need time to calm myself since I was heartbroken... (for you who have read this, you sure know which part it is) :" 
 3. THE CHARACTERS 
 Well. I see some of you are disappointed since the main characters in this book are no longer Kady and Ezra. BUT, I love the new characters MOOOREE than Kady or Ezra. Hanna Donnely is a badass heroine and Niklas Malikov... gosh. I just love Nik so so so much. He's a funny guy. He has a soft spot even though he's a member of mafia, he's afraid in killing people. lol. And the angel wings tattoo on his neck <3 <3 <3 On top of that, Kady, Ezra, and even AIDAN actually also have an important role in this book! 
 4. THE SCI-FI(?) PARTS 
 I mean, Gemina discuss a different 'scientific area' than Illuminae. Gemina is more about wormhole, universe, portals(?), etc. And... that's super cool. I mean, really really cool. Especially for a fan of Christopher Nolan's Interstellar! 
 Although I LOVE THIS BOOK VERY MUCH, I am not blind enough to overlook several shortcomings. I just hope that Amie and Jay realize this and won't do this on the third book anymore... Because, it would be SUPER STUPID if they keep on doing this. I'll hide it anyway since it's kinda spoil the story. P.S. It's also spoil These Broken Stars written by Amie Kaufman. So, I could only suggest to don't open it if you haven't read These Broken Stars. (view spoiler)[It is how they keep all the characters alive. No matter what happen. No matter how you think that it's impossible for them to be alive, they suddenly in a weird (but possible) way would still be alive. Please, Amie and Jay, if you read this, I hope you won't do that in the third book anymore. I mean, several deaths would make the story feels more real and intense. The trick is quite similar with what Amie & Jay both have done in Illuminae. And I would be so disappointed if I find a similar trick in the third book :( It's already the third time for me to read something like that. Since These Broken Stars by Amie Kaufman also do the same trick. So, yeah... I wish THEY WON'T DO IT ANYMORE in the third book. I wish. (hide spoiler)] 
 At last, I just need the third book. Right now. The third book would decide everything. Whether this series would be my all time favorite ones. Or would ended up in 'series with awesome start but disappointing ending'. I just wish Amie & Jay aren't that stupid to underestimate the readers.. :( That's my only concern. 
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 5 biggest fattest stars. 
 I.. I don't know. I really don't know what to say. My brain still couldn't comprehend with what has happened. I need time to cool down and think about how to write a proper review about this. This book is simply AMAZING. I.. I don't know. :((((((( 
 It's just as if this book is written for me, only for me. It just suits me ridiculously perfect and... I don't know.. I JUST NEED THE THIRD BOOK RIGHT NOW, I GUESS. RIGHT NOW. :((((((((