Cringe. Cringe is the word that can best describe the feelings I have after reading 18 chapters of this webnovel.
This story has an interesting premise, with a lot of potential, and it's clear that author has put a lot of effort and thoughts in his novel.
At first, I wanted to read all the unlocked chapters before writing a review but I could not get past the 18 chapter, seeing that at the moment there are almost 300 chapters in this story, there is a chance that this story got better, but I have no desire, nor any patience to read further, still anyone should make their own opinion by giving this story a try, what I'm writing here is just my subjective opinion and the description of my experience reading only 18 chapters, take it with a grain of salt.
The novel is written in the first person, we as readers explore the world from the MC point of view, and have the same knowledge about the world as the MC. I've read a lot of SI fanfics that are written in the similar style as this novel, and never did I have this kind of experience reading a novel from the first person, I had to put a lot of effort to get to 18 chapter, and it's not like it's written in a complex style, or use some sophisticated terms, it also does not have ideas that require some intellectual effort to make a pause to think about them, no, it should be an easy story and an easy read, yet I had to put more effort into reading this story than writing my thesis. A strange experience.
The world is poorly described, we see it from the MC point of view, and he does not show any interest in it, not how it looks, not it's history, not the present situation of the war, not even more details about the enemies. So we get a poorly described world and also can make a conclusion about MC personality, from his lack of interest and curiosity, he thinks a lot but does not make any action to explore what is new.
I don't know what to say about story development, 2 days are described in 18 chapters, well there is a 3 day timeskip, but only 2 days are described. So in two days, he was forced to become a support for 30 hero kids, got a fiancée(also imposed), went to another world with his fiancée, fought the enemies of that world, got another lover, felt in love with the imposed fiancée and she put the idea of the harem and accepted the second girl. So in short, a lot of action and development, the problem is that I can't really call it development, it felt rushed, illogical and superficial, not a great foundation for a story.
Character design, oh... all I can say about other characters is they are one dimensional. We see them from the MC's pov, so all I know about them is all the MC's knows about them, and he does not know a lot about them, I perceive them as caricatures, without any essence only a pretty form, yet MC, somehow, in two days, fell in love with a girl that was forced upon him to be his fiancée, also got romantic feelings for another girl, and also easily accepted the idea of a harem, I know that there is a harem tag and I don't have anything against it but damn is it forced. The MC has improved intelligence, is described as having a clear mind, also he is "thinking" a lot, however his actions does not corelate with his "improved" mind. At this point MC is more of a caricature than the other characters even though he is the character that should have some depth at this stage of the story.
The interactions between characters, is the most cringiest element in the story. The dialogue between the protagonist and his imposed fiancée is infantile, maybe because they are teenagers but damn is it uncomfortable to read, it's like the stories and movies with second rate romance that can only make you cringe. Maybe it was author goal to make the interactions, between characters,(especially romantic ones), at the level of a fairy tale, if so than author achieved his/her purpose.
The dialogue between the enemies and our protagonists can be described in one word-chuunibyou.
It's really just a story about some infantile kids on a hero journey, with unreasonable development.
So in conclusion, all my words are just my subjective opinion based on my experience reading 18 chapters, I will repeat take it with a grain of salt and try reading it for yourself. In no way I want to offend the author, it's clear to me that you are working hard for this novel and I wish you all the best, these words are only my feelings after reading so little, I feel that the potential is there, but I can't stay to read further when, the foundation is so superficial and shallow.
Good luck to you and I wish to all the readers a enjoyable read!