Yeah the headline pretty much summarizes it. It's technically a romcom, but the kind where you're crying for the most part.
It really captures the tropes and the cheesiness of romance movies pretty well. But the highlight is the angst. And evidently, we all LOVE angst.
Okay, starting off, I don't think I need to even say anything about the acting. OffGun are amazing, and so are Mike, White, and Earth. The supporting actors also did really well, especially the ones who played Lynn and Paan.
The OST is absolutely my favorite. Nothing beats it, except maybe The Untamed.
Okay, coming to the plot: I really love it. Maybe its just the angst lover in me but the different spins on unrequited love really got me.
On my first watch I spent the first half basically cussing Kai out. The amount of hatred I felt for him at that point was off the charts. On your first watch you're watching from Third's pov and empathizing with him so Kai really does seem like a total jackass. But rewatching it honestly gave me a completely different perspective on it: the first time round I didn't really register how much Third was responsible for his own suffering. For the most part, Kai was oblivious, and can you blame him? Third barely let his feelings show. But yes, Kai did take Third for granted and was in general as ass who didn't show his friends enough care. The "breaking his heart so he goes back to being my friend" kiss though? Total dick move.
But the key point of the first half was that more than just being in love with Kai, Third was too attached to the concept of romance and looking at his life through a cinematic lens. He romanticized the idea of unrequited love, his favorite romance movies telling him that if he's dedicated enough one day his love will be returned. Which is why I like how Third gets disillusioned and then detaches himself from the concept of love and his dedication to it, prioritizing himself and his sanity. And that is where the switch flips, and we see the rest of the story from Kai's pov. And this is how we slowly start falling for Kai. I'll be honest, nothing in the first half really hurt me as much as that scene with Kai, heartbroken after the movie scene, rehearsing the lines again and again following Third's instruction to be more energetic, but at the same time tears are falling down his face as he realizes this is how Third must have felt all those times. Maybe it's coz he spends most of the series with a smile on his face, but whenever he cries (especially when he's forcing a smile but ends up crying) it just hits so much harder.
The accident arc was kinda not my thing, but it served its purpose I guess. The arc with the junior girl and "I don't want to love you anymore, it hurts" - so. much. pain. But worth it. It was needed, coz Third was obviously still insecure, and Kai couldn't really find the balance between overcompensating for what he did before and actually talking stuff out. He tried to just pretend nothing happened and if he just shows Third enough love he'll forget it, but he just ended up setting himself up for heartbreak. The train scene hits hard coz we feel that sense of abandonment, of being forgotten, but it's also a time lapse of Kai finally letting go of the false hope he had that everything would magically become fine, which actually lasts even until Third comes there - he's still pretending everything's fine and as if he didn't wait all day for people who (inadvertently) ditched him, but Third hugging him is the final straw that makes him break down.
The flow kinda dies down after that though, the last episode doesn't really live upto the peak in this one.
Then there's the side ships. I kind of like how all of their stories play into the idea of unrequited love. Two has been pining after Lynn for years but doesn't realize that he's also on the receiving end of unrequited love until much later - by that time, he actually returns the feelings, but he had been so caught up in his old crush that he didn't acknowledge them. Poor Lynn though, girl seems to have a hard time finding love, first that jackass of a boyfriend, and then the guy who loved her having fallen for someone else by the time they got together. I really liked the Bone and Paan story though, in that they let it remain unrequited. Beyond the awkwardness of the student-teacher dynamic, that's the most realistic course of an unrequited love - the object of your affection probably does not feel the same way about you and probably does not realize that you've put them on a pedestal and are looking at them through rose-tinted glasses. But Bone shows the true selflessness of love, even unrequited, when he decides to choose Paan's happiness over a chance for him to (possibly) win her over. Bone best boy. Be like Bone, everyone.

Overall, this is the kind of show I would consider a classic, a must-watch. There's a lot to love about it, be it the movie references, the pining and angst, the portrayal of romance, the iconic scenes. The verdict is that if you haven't watched it, you absolutely should.