I think this is one of the most amazing books I've read in quite some time. The theories, the circulatory nature, just about everything I found to be thrilling and amazing. However, I would not consider it a perfect '5/5.'
Plot: 5/5
The plot was spectacular; every single character and object introduced was important throughout it, and I'm a little amazed by how detailed the book could get without throwing off the readers as well as how well the authors could stick to the details. Every arc felt significant, if not sometimes a bit long. The whole idea of the Star Stream, the Constellations, the Fourth Wall...everything was both novel and interesting. Any places where the MC seemed to get a little too lucky got wrapped up with a solid explanation by the end.
Characters: 4/5
I think Kim Dokja is one of the best MCs I've seen in a while, if not the best. He was charming in all the right ways, and it was so easy to resonate with him, both his rights and his wrongs.
However, I wish more of the characters had the same depth as him.
Often times, the development of the other characters comes off as abrupt, and I think that it's because the authors introduce the backstory a little too late. For instance, Gil-yeong came off as a little too accepting of the changed world. We know later that it's because he viewed the world as a video game, but at the start, he seems to go along with it as a plot convenience. Or more about why Yoo Sang-ah seems to so perfect; I wanted to see more complexity than a simple paragraph about her upbringing (side note: I don't think this novel, for all its chapters, passes the Bechdel test except for maybe one between Sang-ah and Soo-young (but I think it was about Dokja)). Furthermore, a lot of their stories are short when delved into or are narrated by Dokja. So as much as I could care for Kim Dokja, Han Soo-young, Shin Yoo-seung, and Yoo Jung-hyeok, I could not resonate as well with the other characters or understand them and their motivations.
I think this is more important than other novels because the whole reason the book starts is because Dokja wants to save them and considers them incredibly important to him. So I should be able to understand why he cares so much for them, and yet I find it too difficult because unlike him, I haven't read their stories. I don't understand them.
Story Structure: 4.5/5
I love the POV switches. If it gave more in-depth understandings of the characters as much as it gives Dokja's, I would love it even more. The story structure was solid, and I liked the way the story unfolded.
However. The ending.
I can't say I love it or hate it. I think it gave the book the most impactful ending, but also a depressing one because we never see the end. We have to imagine it, just like Dokja had to struggle to reach the conclusion he wanted. It's the best possible ending for a book so magnificent. And yet, so dissatisfying. Out of pettiness, I dropped the rating a little.
So in total: about a 4.7/5 for me.