3.5 ...? I really, really did enjoy this book. I don't normally read retellings of fairy-tales or anything - not because I don't like them, but to try them has simply not occurred to me! - but I enjoyed this so much that I am thinking of finding more to read ! However, there were quite a few issues with it that I found, mainly in worldbuilding and general explanations of things. 
 One of my main qualms about it, I would say that the worldbuilding was not very strong. The use of the words "hieroglyphs" and "Europe" and "commonwealth" (along with the fact that there was an imperial ruler to the commonwealth ? What... The Commonwealth that WE know was created AFTER the British Empire ... lmao ...) did not seem right or make much sense or understanding ESPECIALLY because of the lack of explained history to this world. As well as that, this is set in 'New-Beijing' (part of the imperial Asian commonwealth ... WHAT) but then it might just as much be set in England and Europe, the USA etc ... there was nothing that specifically placed it in China or anywhere remotely 'Asian' seeming. I kept forgetting and picturing Peony and Pearl with like, blonde ringlets and stuff like that. 
 Apart from this, there was the fact that cyborgs were seen as second class citizens and below the rest, even though they are just normal humans with electronic parts where they had injuries ... a bit like prosthetics. Yet, the reasons for their low standing in society is never really explained either ! I'm not sure if it's just some ridiculous (and unexplainable?) prejudice like racism or some equally ridiculous prejudice like homophobia which started, I think, with religion etc; sex ONLY for procreation. Is this prejudice against cyborgs one of these? I THINK it is because they are seen as less-than-human because they have 'robot parts' in them, but I'm not sure this makes so much sense because people have things similar to this in prosthesis and pacemakers etc. and they are not looked down upon to my knowledge... So how was this hatred evolved ? 
 I liked the aspect of the people - Lunars - who live on the moon, though again I would like more of an explanation as to HOW and WHY they came to and still do live on the moon. Have they always lived up there, just unnoticed? Did they go up there when they started developing these Lunar powers, or to get away from WW IV or even WW III? Did they come from somewhere else entirely? And has the moon's atmosphere been made suitable for ~humans~ to live on? I'm not sure that they are human... if they're NOT, are they aliens? If they ARE, how did they get their powers? Do they constantly stay inside where they have access to a suitable atmosphere? Are they adapted to the atmosphere on the moon, and if so how do they come down to earth? I would like to find these things out, and I would like to see more of them and see them in more detail in later books, hopefully. 
 Even though I understood that it was a retelling of Cinderella, it took me an embarrassingly long time to get the significance of Cinder's foot ... come on Nadia ! ... I have also JUST fucking realised : CINDERella. Jesus, Nadia ! I especially liked the sci-fi aspect of this, and I thought that it was quite original, making Cinder(ella) into a cyborg and to have her seen as less than the rest of her family just about everyone because of that. I think it is actually a stronger reason than the real reason they disliked Cinderella, just because she was their step-daughter / sister... There was also the other storyline of Levana trying to wage war on the earth, which made the book even more interesting. Of course, it WAS a bit predictable who Cinder was(view spoiler)[, that she was really princess Selene (hide spoiler)] but hey, whatever. Young adult is normally predictable like that. 
 I liked that at least one of the step-sisters was nice, and this made it seem less like every girl being out against Cinder, which is kind of a think I remember I used to see a lot in YA books. (view spoiler)[It was sad that poor, good natured Peony died! (hide spoiler)]With this, it was nice to see that most of the time Cinder did not feel that weird sense of superiority that she was Different To Other Girls(tm) because she dressed differently and was a mechanic ... she DID get a bit like that with liking the prince, but not to a large extent and that calmed drastically when it turned out that - oh shit! - she DID like him! 
 I personally did find Kai himself annoying at first, though he grew on me later, when he had finally stopped moaning about the fact that he could see his dad when he was dying, especially as so many people didn't even have the option ! I did like him much more later though, refusing to marry Levana until he thinks it is the best thing to do for his planet/country. I think that maybe he was shown to be a bit petulant in the beginning when he was a prince, to show how quickly he was forced to grow up(view spoiler)[ once his father died and he was thrown into being emperor (hide spoiler)]. I am suspicious of his adviser - Torin ?- as there seems something off about him, but I'm not sure what it may be, if anything. I also found the doctor interesting. It was quite obvious from the beginning that he was a Lunar, but I did really enjoy the way that you couldn't properly tell if he was a 'good' or a 'bad' character until later on in the book. 
 Basically, I did very much enjoy this book. One and a half stars was taken off because, fundamentally, I needed MORE to fully understand it. It's almost like Marissa Meyer has this in her head for so long and was so familiar with the history and circumstances of this story that she forgot that not everybody else is too. Or maybe I'm expecting too much from a YA novel.