The character development of MC was really obvious. He was like a loner at first. Acts alone and keeps his thoughts inside. After meeting one classmate who knows him in reality, an enemy he solved two instances together with, gradually he starts to participate to the group as a team. He shares his thoughts and speculations. Afterwards, he also started leading the others. His emotions became more open. Sometimes he actually looks cute. His emotional struggle with the ML wasn't annoying also. It was like everything just comes naturally for them when it's time.

ML was a bit yandere, possessive, and obsessive, however it was just thoughts. Although I was kind of irked about the tying up MC in the dream without consent, but it was just like two or three times. In the later chapters, he became more restrained with his dirty thoughts and cherishes MC more than himself. He respects and loves the MC too much to hurt him and take away his freedom. He was one of the best ML that I encountered where it feels that they're both equal despite the differences in status. He was supportive and ready to help the MC in anyway possible. Keeping him from harm but also letting him grow on his own. He doesn't intervene to MC's instances but most of the time, he keeps MC safe in and out of the instances (like in the orphanage instance), support him emotionally, and ready to sacrifice for him in any way possible.

Side characters are a bit bland at first. They were like foils to make MC look "great" and "OP", however in the later chapter, although some of them rely on him, they actually do their part. Ye Zeqing for example uses his talent to perceive the emotions of the ghost or sense them. Wang Huai was a leader like person who do his part in protecting his team. And other characters who also speculates and tries to solve the problem.

I also love the ghosts the MC "collected". They were all more or less tsundere. They have a grudge to MC for "abusing" them but also there ready to help him anytime. Also, they love tricking other ghosts into falling into the pit the MC prepared lmao. All of them were actually so cute.

As some reviews said, the instances in the early chapters might seem cringe, however as the instances progresses and became harder, it also became more enjoyable. Sometimes, you'll just be like "how?" and "so that's how it is". The MC was both smart and clever. For example, the trick in the rules of the Lingshi Mountain arc, the Scary Stories arc, the Styland arc, the train arc, and many other instances in the later chapters.

the explanation that he can befriend ghosts and has no fear because he has no emotions doesn't fly; excitement is an emotional response and he's always excited when it's time to solve the puzzle. his emotions are dampened and I would go so far as the say he has some autistic tendencies, but he does have them.

I'm not a big fan of the "I will stalk you and sexually harass you until you give in" type of ML and the NC dreams, among other things, is way beyond Not OK. the author seemed to realize it and eventually stopped with the worst of it and the ML stopped harassing the MC through the book and started showing up in person. He continues to stalk the MC, who says he finds it cute, and is possessive as hell, which the MC says makes him feel safe. this is a completely alien way of thinking compared to my own and my friends/family, and I don't get it. I lost a lot of my enthusiasm for the MC once he threw away his initial independent nature and concluded that he enjoyed being owned by the ML.

behind changing nicknames from Sherlock to Moriarty. the first guy knew his real name and game name already, so why does it matter that the second guy also knows his real name and game name? the change in the nickname seems to be there purely for causing comedic misunderstandings between two side characters and makes no logical sense within the story. why does he suddenly care about a name when he hasn't cared about much of anything (except playing games) since the whole story started? then he adds a third name, just so the author can write more unnecessary verbal infighting between fans on the forum for filler.

once the prison instance is over. maybe the author didn't want to spend more time actually writing about them building up their relationship; they just jumped from luke-warm to scalding with very few steps in between. the MC went from "I don't want to fall in love" to "I don't know if I like you like that" and then skipping directly to "Our bond is eternal and we will be together forever." some people will find it romantic, it just made me roll my eyes and move on.

in one scenario the MC examined a body of a person that, in their point of view, opened a black box and then promptly dropped dead after looking inside. The MC looks at the body, determines that it was dead for half the day and then immediately turns to another person to tell him the answer of what was in the black box, which was memories of how that person died earlier. The problem is, this happens almost immediately after looking at only one dead body and then asking the ghost delivery man some vague-ish questions, before immediately jumping to "oh that's the memories of their death!". It's not a dumb or unreasonable answer, it's just that the jump was so fast it felt like it went from Point A to Point M with nothing about the in between steps.

Didn't expect that Xiao Li will become a god like lololol his name is "god of fear and badluck" but duh it suits him as he scares all the ghosts and brings bad luck to them. But as a god, he can live with the ML forever!!!!

the devil had hinted that ML might be some god or a higher being

MC as a kid gave ML a popsicle once and ML has been stalking him for years after that and fell in love. Literally their only interaction beforehand

MC figures out ML is the book himself and willingly chooses to be with him (because due to his mother dying and leaving him or something like that MC only wants a crazy possessive lover who will care about him and nobody else