So I just realized for some odd reason I never posted my review on Goodreads for this....awkward. But here it is now! 
 Review Originally Posted On The Sassy Book Geek 
 Let me say this first: Not as good as "Illuminae". 
 I gave "Illuminae" 5 full stars despite the minor issues I had with it and so my expectations were extremely high for "Gemina" and I have to say I was a bit disappointed with it overall. However, this book is still getting a 4 star rating because it's still a great book despite not enjoying it as much as the first book. 
 The Plot 
 First of all the plot stays really true to what Kaufman and Kristoff did in "Illuminae" in which case I mean it's full of action and death mostly. However, I felt like the plot could have used MORE suspense and that survival feel that we saw in the first book. I didn't feel as...thrilled as I did during "Illuminae" my adrenaline wasn't pumping as much (well as much as it can be while reading a book). Remember all the insane plot twists in "Illuminae"? Yeah. Didn't really see them in "Gemina". There were a few that I enjoyed but for the most part they were either not that great or a little bit predictable. 
 I did enjoy the inclusion of alien life forms in this book because come on what sci-fi series would complete without that? They were terrifying and interesting and probably one of my favorite parts about this book and I almost would have enjoyed them playing a bigger part than they did. There's also a kind of Russian Mafia in this story too which is pretty much guaranteed to always make things more interesting. Then we have space pirates/mercenaries invading a space station and even a time paradox which may or may not be a little confusing. 
 The pacing of the story was a little off in the beginning of the book by which I mean it was slow and a little boring at first. I'm here for the spaceships and death! I don't care about a teenage girl and her boy problems, damnit! Anyways, the pacing picks up as the story progresses until suddenly you're done with the book, very much true to "Illuminae" style. 
 Of course we have the same awesome format in "Gemina" that we saw in the first book and even the inclusion of some of author Marie Lu's illustrations. There's also a few hidden things in the book if you pay close enough attention, one being the names of several other YA authors included on a list of casualties. So I thought those were some cool little treats to include for us booknerds! 
 I enjoyed the story at the ending the most where we got to finally see some of the characters from "Illuminae", *cough* AIDAN *cough*. It really livened things up in my opinion. 
 I would also like to take a moment to discuss the thing that irritated me the MOST in this entire book and while I will not mention names I will mention a sort of situation that might be considered a spoiler soooo.... 
 And also! 
 (view spoiler)[The single most irritating thing in this whole book is: HOW DEAD PEOPLE DO NOT STAY DEAD!!!! This is the most proficient way to piss me off and make me resent the character that did not stay dead. The whole entire point of killing a character off is to make us shocked and it really ruins that when they were fine the entire time! Quit ruining it! 
 I also feel like that twist is a little "been there done that" considering it was used in the first book as well. (hide spoiler)] 
 The Characters 
 One word for the characters in this book *ahem, cough* NOOOOOOOOOO! 
 Really by this I mean Hanna one of the main characters, couldn't stand her. I thought I had issues with the characters in "Illuminae" but oh boy they look like gold compared to the characters in "Gemina". Hanna starts out as a spoiled, entitled teenage girl and really that shows in her attitude a lot of the time. Does she develop? Yeah, I guess but she still never failed to annoy me. I thought Hanna acted really selfish through a lot of the book, sorry sweetheart but the world doesn't revolve around you...or your boy problems. 
 Nik, the other main character, I actually thought was pretty decent. He was funny and a little more down to Earth (space? space station? not technically Earth...) than Hanna was. Although his constant flirtations with Hanna were by far the most annoying thing about this book. Still liked him though. 
 I liked a couple of the secondary characters as well and the villains for this book were pretty intimidating which I LOVED. 
 Overall though I just felt that the characters weren't all that great in "Gemina", I didn't feel a connection and I really could have cared less about most of them. 
 The Romance 
 I briefly mentioned the constant flirtations between Nik and Hanna but I'm here to say it again. This took so much away from the plot itself I thought, it wasn't cute or funny it was just extremely irritating because of how constant they were. Seriously! I do not exaggerate! It's happening all the time throughout the entire length of the book. 
 There's also insta-love, not in it's traditional form but it's still kind of there. If you've read the book you might know what I mean and if not you'll find out. There's also a love triangle that once again isn't your typical love triangle but is still technically a love triangle. Both of those things annoyed me as well.... 
 Overall not impressed with the romance whatsoever but no real surprise there. 
 In Conclusion 
 I DID like this book but it was not as impressive as "Illuminae" in my eyes. I'm hoping this is just a case of "middle book syndrome" and the next book will live up to expectations. 
 What I Liked: 
 The unique and fun format 
 The fast pacing (although it was a little slow to start) 
 Aliens 
 Space mercenaries 
 Time paradoxes 
 The inclusion of characters from "Illuminae" 
 What I Didn't Like: 
 The thing in my potential spoilers section 
 Hanna, the main character 
 A lot of the other characters were bland 
 The romance 
 The constant flirting which was more annoying than cute 
 Recommend? 
 If you've read "Illuminae" I definitely recommend continuing with "Gemina" but I would maybe lower your expectations a little bit so you don't end up like me. If you aren't sure about this sequel you can always wait to binge read it when the last book comes out!