A vertically filmed micro drama (I rate these on their own sliding scale). General Spoilers below.
Okay if a fan of the lead actors because the dynamic between their characters is uncommon and interesting. They kept me watching through annoying characters, tropes, and ridiculous plots.

The lead's disgruntled, impassioned bicking was mostly fun and it was endearing to see them transition slowly into seeing each other in a new light and caring about each other.

However, the romance ended up not being that satisfying because:
1) The last 1/4 focused on ridiculously crazy plot shenanigans instead of the growing feelings between the leads.
2) The interest felt lop-sided. Fairly early on the ML starts showing interest in the FL, softening towards, then being attracted to her, and wanting her to like him too. The FL's progression takes a lot longer to start, and it doesn't go as far. By the end, I only believe she's starting to be fond of him but not that she loves him. She shows no desire or physical attraction to him either other than stating that he's handsome. She doesn't even look tempted when the ML tries to kiss her.
3) There are no fully consentual or sweet kisses shown (like it's okay to show a kiss being forced on a woman but not okay to show her wanting a sweet kiss for herself). There are some sweet moments, but very little intimacy overall.
4) The ending is super rushed. Both grandpa's reveal the truth separately, there's plot craziness, and then the short ending scene.
5) The important last tender moment between the leads is ruined by the background sound. It sounds like someone over a loudspeaker giving a Christmas day speech. It's distracting and makes it difficult to hear the ML clearly as he professes his love.

It's a missed opportunity that the script doesn't have either character grapple with the confusion and possible internalized guilt for starting to love someone other than their childhood love. As a result, things (emotions and character logic) feel shallow. Also, the kids seemed about 6 years old when they met in the mountains, only had a short time together, promised to marry each other, haven't seen each other since, and yet are adament about staying chaste until the other can be found. It's not a believable set up at all.

The FL is overly competent except when the plot needs her to be a "regular girl". Example: she's a medical genius and a martial arts master, yet she can't shake of the ML when he makes a couple advances on her that she doesn't want (he doesn't push too far though).