I stumbled across this series by accident, because it was recommended to me on YouTube. I decided to watch the first episode after seeing how short it was, and after that I watched the second one, too.
I loved it.
This series has a quality that I greatly appreciate, and that is its naturality. It's grounded, realistic and very normal, which is not something a lot of series dare to be. It portrays two characters that could be someone you know - they have a history together, they have an existing dynamic, and exist in a preestablished setting (that we, as viewers, are not familiar with). They mention their families, but not in an info-dump-y sort of way, but rather in a way two best friends would - they already know their families, so why would they have to explain further? The viewer is not given that information, and it's okay, because it's not the focal point of the story. We simply have happened to meet them at this point in their life, and that's the extent of the 'lore'.
The acting and how it's filmed is refreshingly natural (as I've already stated), sometimes so much so that I would feel awkward because it felt like I was intruding in two real people's intimate moments. The dialogue flows easily, and it doesn't feel scripted - it's random, it's comfortable, and it feels realistic.
There are no crazy plot points, no mafia bosses or CEO-employee shenanigans, no past trauma, nothing. This is a story about two people that are completely average, do average things (like go to the military, or receive pre-made food from their mom) and just like each other. This is it.
The shots are slightly shaky, lingering and unpretentious - they make you feel as if you're watching the scene in real time in the same room as the characters. The music is noticeable, but discreet, and fits the vibe of each scene.
This series overall reminds me of SKAM Norway - the dialogue that feels like improv, the slow and drawn-out scenes, the focus on the character's emotions rather than the plot itself -, which is a compliment, by the way.

The only thing I could point out that I didn't like as much as the rest would be the conversation that they have in E2. I feel like they could have cut it and we would have been fine. I liked the first episode because it didn't explain much of their background, or their relationship, and that's what made it so realistic (people don't walk around telling their backstories to each other, especially when they're close friends, just because the viewer isn't aware of them). However, E2 felt the need to fill in some blanks, and had Jae Sung explain a bunch of anecdotes to his partner, whom was probably already familiar with them and didn't need to be reminded. It also doesn't seem right that they didn't talk about them in those two months before Jae Sung went to military camp - they had so much time, what happened there?

Despite that, I still love this series. I wish they would give the characters the chance to evolve and interact a little bit more in a new season, or episode, or whatever. I'm amazed that they could captivate me with less than 20 minutes of runtime.