The cinematography and acting are great. The stories are interesting, tho sometimes it tried too hard to make me feel and failed at it.

But the portrayal of autism is not so great. Geo-ru doesn't feel like a person, he feels like a mascot. He's utterly static in his character, doesn't develop at all through the story, other than getting over the death of his father. He can only talk in a totally robotic chanting voice 24/7(that's not how flat affect works), lightly bang his head against the wall when stressed(that's not how meltdowns look, they are usually more violent and dangerous for everyone involved) and keep talking about fishes when under pressure(special interests are just interests people on spectrum pursue with passion, they aren't tantrum-esque coping mechanism for real-life stress).

All the while he is unconditionally supported by just about everyone in the story, his father, his mother, his (not) gf, his uncle, the trash guy, his father's co-workers, the prosecutor lady, the people at the aquarium, the lawyer.....everyone is super patient and understanding to him, and is way too eager to run to his rescue if he is but in slightest danger of anything. Even his kidnapper was nice to him.
This idealized sugar sweet life is not what most people who are autistic live.

Examples of some situations that could have given him character development but where unexplored by the writers:

-When they go to clean up crime scene, Na-mu says she's scared. Geo-ru says the murder happened two weeks ago, and there is no one here, so there is no reason for her to be scared. Here Na-mu could have said something among the lines "Even though there is no reason, I am still afraid, don't invalidate my feelings" and then they could have discussed it. Geo-ru could have tried to understand that people can feel emotional states even if there is no logical basis for them, and learn something from it. Alas, Na-mu is his devoted 100% supporter, and didn't say anything.

-When Geo-ru sees some guys smoking in the toilet, he throws a tantrum and tells them its forbidden and threatens them and so on. In return, they bully him. Shortly afterwards, the uncles runs to his help, and everything ends up "fine". Except it doesn't. Here Geo-ru could have had a reflection, maybe reach some kind of epiphany, that not everyone follows or respects same rules as him. That maybe next time he shouldn't act like that towards strangers. But alas, he thinks nothing.

-In one of the flashbacks, his father tells him that the key to understanding other people is putting themselves in their own shoes. No shit, genius. But that's the thing with autism. People on spectrum can't do it, even if they try, even if they know in theory what they should do. When autistic person puts themselves in shoes of someone else, they overwrite the person in question with their own "self". In other words, "I wouldn't do it, so this person won't do it!", "I wouldn't believe it, so this person won't believe it!", "I wouldn't say it, so this person won't say it!". This is called impaired cognitive empathy and is one of the key characteristics of the autism spectrum disorder, one that causes most problems with social functioning in a neurotypical world where people take such skills for granted.
If Geo-ru was a well written autist, he would say something like "I try, but fail!". He would have argued against his father, instead of obediently nodding his head like a puppy and agreeing to everything, as if it solved anything.

There is also inconsistency with how his autism works. It works when the plot needs it, and shuts down when the plot doesn't focus on it. One example is Geo-ru getting a meltdown while driving, possibly from overstimulation. Autistic people are very sensitive to sounds and light, so it kinda makes sense why he is discouraged from doing it, and quite an achievement he even has a driving license in the first place. But in the last episode, he goes to a loud af underground MMA ring, straight into a huge croud of screaming people, flashing neons and squeezes his way through said crowd. Then proceeds to analyze the situation calmly and comes up with a solution to the challenge ahead. Excuse me, what?

In another example, Geo-ru fails at understanding people and reading the mood. Except for that one time when Sang-gu and social worker were arguing about the deceased couple, and Sang-gu says something insensitive. Awkward silence follows, and eventually Sang-gu leaves. Only then does Geo-ru resume conversation. How did Geo-ru notice that? It would be much more in character if he completely failed to read the mood, and kept talking about the job without noticing the tense exchange between the other two.

And how was his nonverbalism cured? At the age of ~6 or so, his parents took him to Aquarium, and he suddenly started talking fluently looking at fish, even tho he had never ever spoken before in his life. Excuse me, what? Never mind the neurological causes of nonverbal expression in autism, a person who never spoke before would not be able to speak so well on their first try. They'd need practice. Their vocal cords wouldn't be used to making sounds, and they'd have low control over pitch and volumne, among other things.

So yeah. Quite good, wholesome slice of life series. Not that sad tbh. And with not so great portrayal of ASD. For a better portrayal of this misunderstood and misrepresented disorder, I recommend Taiwanese drama Victim's Game.