Honestly this is nowhere near as bad as the makjangish and super silly setup would suggest.
I have two big problems with the show.
The first is that the OTP romance is not very believable. I think acting shortfalls are definitely part of this issue & the chemistry was just not enough for me to fully immerse myself in their relationship.
The second is that the ending is extremely low effort. There was all this crying/suffering/hardship & then everything just worked out senselessly, also following the always annoying separation followed by a 1 minute happy ending formula. It's better than people dying I suppose, but not by much. I don't know if this was live filming or not, but it sure feels like it. Then again, it's quite normal for kdrama writers to not give a fork about well thought out endings, so that could be it. (This is pretty much the industry standard now, if anything.) On a positive note a well thought out, reasonable ending would've been exorbitantly difficult with the setting we've had, so perhaps embracing the silly is not the worst thing in the world. I would hugely prefer though if writers made scripts that can be wrapped up in a way that makes sense, instead of making convoluted messes & then just yolo-ing the ending.

As for what I liked.. There is a lot of reasonably well written dialog existing outside of the plot-driving conversations. I liked the moody presentation & the pink filter was part of that too I suppose. I liked the visuals on my color calibrated displays, but I can see why someone would hate this, if watching the show on an LG oled TV or a Galaxy phone..
The OST is pretty good too!