My parents always told me to never hurt somebody's feeling, so either you say good thing/praise them or never spoke a single word... So if you want to have an opinion or criticize, it's better to use gentle words rather than using harsh words like that, and get used to providing solutions so that they can improvise when you criticizing something.
lol ok, I have time to kill. Here's my thoughts on the first two chapters. Doing a play by play of a chapter is more effective for communicating my criticism but it also takes a bit so I'll only do a few critical chapters.
Starting with chapter one. We start very typically with a engagement annulment scene, and then a flashback to how things got here. This flashback then lasts the whole chapter and is just a summary of every single important event since Emi took control of Remilia's body. This is just bad storytelling. It certainly gets the job done, but in the most heavy handed way possible. First, the flashback is not told like a story, it's simply a collection of events thrown together, basically a sparknotes version of Emi's life as Remilia. Second, the author hasn't established any interest in these characters before just exposition dumping their past on us. The bad structure of this chapter makes it boring enough, but to make things worse, I don't even give a damn about these characters yet. This is also the best place to discuss Emi's character, as it is forced down our throat by the narrator. Her almost singular character trait is that she is nice, with a side of airheadedness. In an attempt to compensate for this bareness of character, her niceness is cranked up to 11. The quirk in her character is how selfless she is. Unfortunately, this kind of characters is extremely cliche, and not even in another genre. It's just the prototypical shoujo romance protagonist. In the flashback some of the things the original herione did later in the story are shown, and they almost perfectly mirror what Emi does. I'll admit, there's nothing wrong with a character like this and in a story as meta as this they could serve an interesting role, but this never happens. Our protaganist Remilia "falls" for her just as every love interest in this story does and on a wider scale, every love interest in the genre has. There is no deeper analysis of this type of character, and nothing new is said. Additionally, the way this kindness is show is cliche, and even if it wasn't is would still be silly. Emi comically sobs on behalf of every character and she tells them to not give up. This solves all her problems, along with her absurd physical strength. I'm not even going talk about how she is a Mary Sue, that's just standard in the genre. All in all, this makes it very difficult for me become attached to Emi at all, which is problematic later, because the whole story is a revenge on her behalf. Finally to end the chapter, we have the comically evil reincarnated original herione foreshadowed, ragebait facial expression and all.
The main purpose of chapter 2 is to introduce Pina. This chapter is actually a masterclass in ragebait type plots and the art is really good I respect both of these things, but that doesn't mean it's good writing. It suffers from many of the same flaws as chapter one, which much of it having bad, summary-like pacing, but it also has some different flaws. To start, Pina is introduced. She was some shit eating expression on her face, as she does at all times. The scene where she barges into the student council is fine, but afterwards we get her first characterization, if you can call it that. She displays her intense cognitive dissonance by rebuking Emi for getting close to the main characters while having the same goal herself, and then claims the story as her own with flimsy reasoning on page 17, with maybe the most hilarious expression yet. There is really no problem with this scene in essence, the problem is how heavy handed and blatantly rage baity it is. This could work in a good story, people try to get a rise out of people in real life all the time and a little bit of comicallness isn't that big of a deal in a comic. However, the problem is that there is not indication that Pina isn't acting with "impure" intentions, as she is presented as totally genuine. All of her expressions are coded as genuine and she leaves immediately after without waiting for Emi's reaction. This gives the idea that this confrontation reflects the geniune mental state of Pina. Unless she is mentall ill (which the author gives no indication of or explores) his puts her beneath the most cartoonish of cartoon villains. She possesses no semblence of humanity, being the incarnation of things that provoke anger. Throughout the chapter she continues to display zero self awareness. A villain this bad could ruin the best of stories. Not only is she unrealistic, she serves no narrative purpose in furthering a theme or developing the character of the protagonist. She is just there to make the reader anger and keep them reading to see her downfall. Next, the betrayal of the love interests. I'll take information from the next chapter for this part because it's pretty important. In chapter 3, it's revealed that Pina used love potions to sway everyone in the academy to her side. This is actually a good explanation for a phenomenon that often goes unexplained in stories like this: why do the seemingly decent love interests betray the Villainous, who is clearly a better person? However this becomes weird later, when all of the love interests are treated as being nearly as bad as Pina (clearly designated as a revenge target on page 56). This is given a slight justification in chapter 3, as it's explained that Emi warned the love interest about food from Pina. However, not listening to such advise is not only out of character for the love interests who all seem to think very highly of Emi, but it also it only really amounts to a minor character flaw. The sole villain in this story at this point is Pina, but every single person that has been brainwashed is treated as having a similar level of responsibility. I could write more, but I think my point has been made.
These two chapters show a lot of the problems that I have with the premise of this story. I'll maybe write one more about a later chapter that shows more pacing problems and some of the things about Remilia I don't like if I have time and can bear to reread up to that point. I'm curious if anyone has a good response to my analysis as many people really love this manga and consider it to be "quite fresh", which is a perspecitive I do not understand. I usually speak my mind harshly because it's more fun to but I'm open to other interpretations of this work.
tl;dr: The story often takes the form of a crude exposition dump and has poor pacing. The motivation for revenge is unstable due to poor motivations and the reason being hard to get attached to, and the villain very silly. Overall I would stand by my statement that this is trash and would give it around a 3/10, mostly for the art.