I have conflicting feelings about this one. Obviously the drama is great, there is no denying that, but I'm a bit disappointed how predictable & cliche the 2 main elements of conflict/drama were and how much time they've wasted on them. (Oh no your mom, oh no my mom .. & reverse love triangle with autistic brother) Ultimately I'm happy how they resolved these things, but it was somewhat draggy both times. The first 4-5 episodes were absolutely top tier, it had one of the best openings that I've ever seen, but then the ball dropped quite a bit. I've heard the production team received many complaints about two scenes in episode 3 (what a great episode it was btw). They could have dialed things down a bit to avoid further controversy, oh well live filming is the worst :-)
The drama received praise for the authentic portrayal of Autism Spectrum Disorder. Yeah sure, the actor did a phenomenal job, way beyond what I have expected of him. (I did not like the actor before) The main problem is I don't like how every time a person with a major disability shows up on korean TV, they would make the actor keep bowing down perpetually. It's like they want to convey a message to the Korean audience, he has a disability, but he is extremely sorry, forgive him, he is bowing down so politely, all the time. Sure, people with this disorder would not meet your eyes in a conversation, but this whole bowing thing is at best stereotypical.

The acting performances were great, the leads were incredible. I have never thought that one day Kim Soohyun would show off the charts chemistry with any actress, but he was really awesome. I think the military did him good, his acting improved a lot, his performance in emotional scenes especially was hugely more convincing than before. I did not really know Seo Yeji before, but I have only praises for the actress. She reminded me of Jennifer Lawrence's best performances. (not Hunger Games). The supporting characters were all extraordinarily good as well, at first I was a bit miffed about seeing 2 out of 5 of my least favorite senior actors in the show, but I guess the casting was spot on, since I got used to them pretty quickly, as opposed to being being super annoyed seeing them in every other drama.

The story despite being a bit draggy at times is certainly above average, the writer successfully delivers on wholesomeness, healing & romance. Sure there are quite a few problems, such as the show could have deserved a lot more depth, it absolutely sucks if I try to judge it as a medical drama.
The comedy is off the charts good, although there was a lot less of it nearing the finale. I have been feeling a bit down lately and I had hard time laughing, I started to doubt whether I can still appreciate humor as I had before, but in this drama there were quite a few moments, when I ended up laughing out loud, or spitting tea onto the carpet, it was sensational and still bittersweet at times. The last episode was great too, thank God it was a sufficiently long happy ending, the kind that I like best, long, but not too long. There was even a major plot twist, that I should've seen coming, but ended up surprised.

Product placements have been becoming increasingly immersion breaking in recent years. This drama has many very clever barely noticeable placements, kudos for that writing interns, but good God those car ads were just too much. There are several scenes specifically purpose written, where we are shown how incredibly good the brakes are on that specific car brand & to top it off all the older unbranded cars kept breaking down.

The deer! The first time I heard the deer making that sound I was like OMG, what the hell is that, but after going on Youtube I had that TIL moment, yep deer can really make a sound almost identical to that. I've seen thousands of deer in my life, but I have never heard them making any crying sound like that, but it seems to be real. For more information check out this YT video: https://www.youtube.com/watch?v=RAkgkyeHpOc

The audiovisuals were spot on of course. The OST had quite numerous tracks, it's nice when we don't hear the same song playing 6 times in every episode. There were some really cool lens flare effects, perhaps they used vintage lenses to film some of those bike riding scenes?

Overall 8.5/10 seems fair. This is the best 2020 drama that I've watched so far. I'm sure I will eventually watch it again and I might end up adjusting the score too, who knows. (I liked it a lot more than Crash Landing)

edit: 2020 is over, but thinking about it now I think Hospital Playlist is the better drama, though it's not nearly as fun..

edit2: I decided to up the score a little, nitpicking is fine and all, but this is really a great drama.. :-)