Three stars only because I had such high expectations after These Broken Stars, I found this to be a good reading experience just incomparable to the first book. On one hand, I really appreciate that the authors didn't try to push the love story too hard given that I've always found those VERY unrealistic when the characters are also on opposing sides of a brutal war. Either the romance ends up being unrealistic or the characters end up being caricatures. On the other hand, that meant that Flynn and Jubilee never seized my heart and squeezed the crap out of it the way that Tarver and Lilac did - and that's despite the fact that I started out straight up hating Lilac, thought Tarver was the dumbest name ever, and almost stopped reading These Broken Stars because I thought it was going to be YATYA (Yet Another Terrible YA) novel. 
 I just feel like I was much more invested in the characters from the first book and that the storyline was both more compelling and also allowed for deeper exploration of their characterizations and relationship. It's hard to pull off a brink-of-war plotline though, so kudos to the authors for even trying. It's just that while the twists and character development in These Broken Stars really surprised the heck out of me and brought me to tears/left me in genuine shock, This Shattered World was very...expected. The insane bad guy (yes, we get it, he's insane, no need to repeat this 10x) who will cross all lines, the mutual experiences of lost close family members, etc. Also, there actually just wasn't really room for character growth. Sure, Jubilee broke rules and became less of an obedient soldier, but I felt like the whole child-Jubilee vs. stone-cold Lee thing was a tad oversold, so it ended up being less convincing. Flynn, on the other hand, doesn't really change in any way. 
 One thing that REALLY irritated me was that I listened to the first four chapters of this as an audiobook before reading the rest in book form, and the descriptions of both Flynn and Jubilee were quite honestly gag inducing. Something about a chin so amazingly chiseled (does anyone genuinely describe a real living being that they've met like that, even in the privacy of their own thoughts?) and how Jubilee was "so very hot" or something like that. The ever so long description of Flynn sounded like two 16 year old female teenagers were describing their crushes, and Flynn's narration of his attraction to Jubilee definitely did not sound male. Tarver sounding distinctly feminine in his narrations was something that other readers had brought up in These Broken Stars, but I forgave that because I felt like a) the language itself was beautiful enough that it was ok to sound so inauthentic and b) his character being all artistic/poetic helps excuse his, er, flowery thoughts. 
 Maybe it was the fact that I listened to it on audiobook rather than skimming over it, but I cringed so hard listening to the descriptions of both characters when they were introduced. No, just no. Thank goodness it was mostly limited to the introductory chapters. 
 A+ for the slowness and lightness of the romance, though. Neither Lee nor Flynn are the kind of dumb characters who would let their hormones take precedence over, uh, terrible atrocities, suicide bombings, murder, did I mention a planet on the brink of war? (how many YA novels fail on this point?) etc. I LOVE the fact that the authors didn't just have them profess eternal dying love to each other - rather, the characters develop attraction and mutual respect, they work together, and they want the chance to explore whether it might become love.