Ledgem

No, he's actually sort of a victim. The villain is really his mother.

I had mixed feelings about it for sure, but actually I think it's kind of beautiful. I think all of us expected that we knew who was being reborn as who, but in actuality, it was Do Jun who was reborn as YW. There may be some plot holes, however, as it seems the events that happened in Do Jun's life really did occur (we see the prosecutor remembering the same wording about her appearance and clothing), yet that would mean Do Jun had the knowledge of the future from YW. It's interesting.

I don't agree with your takes.
- The male lead rejoicing over the prospect of her death showed just how trapped he felt, and how miserable he was. It's not normal, but then his situation isn't normal. He was being treated horribly and it shows how unhappy he was.
- Their distance was addressed. It's only hinted at until the end, but the hints were strong enough, I thought: they were going to have a child, and then Hae-In lost the child. It's unclear throughout much of the series if it was an intentional abortion or a miscarriage, but that type of event can change a relationship. That was likely the catalyst to growing distant for them, although they were already in a situation where Hae-In's family was working against them as well.
- The illness was explained: she has a rare and unique brain tumor. Was it overly realistic in how it was portrayed? Not entirely, but they didn't make it too horribly outlandish, either.
- The scamming and dropping of their guard is absolutely believable. This family got rich and got their positions not because they were overly smart, but because of the founder of the Queens group, Hae-In's grandfather. It's clear that there's an element of greed and self-absorbedness within the family. It made for touching personal development when they were cast out of their lifestyles and began to appreciate "real life." I'm surprised you'd harp on that part, and not on how it was a stretch to watch the villains plot and coordinate as well as they did, for as long as they did. But even that didn't feel too awful - I could suspend my disbelief enough to enjoy it.

It's not a 10/10 series and I certainly wish that the joyous parts were longer, but it was a really touching series that seemed to remark on the importance of marriage, family, and personal bonds.

NF9 is a made-up chemical that the series claims is used in the production of electronics, possibly among other applications. The trouble is that its production results in radioactive waste that seemingly can't be processed easily, and that the corporation dumps as radioactive water. The radiation is what caused the city's population to have a significantly higher rate of cancer development than in other cities.

I sort of concur with Kcalbdnomaid. My wife and I enjoyed the first half or so, but then the usual tropes of arguments over miscommunication came up. "Bad" characters were either never redeemed or punished (not that we see, anyway). Korean dramas are usually good about letting viewers experience the full rewarding feelings, but this felt more like an average Chinese drama when it came to the "feel good" aspects. I have slight regrets about choosing to watch this over another series.

The girl who took the photo had it stored on a cloud service. She provided them with the login information for that cloud service. They memorized it and were able to access it on the next loop.

Please don't. The ratings are public and many of us use the ratings to determine if a show is worth watching or not. In general this website has a problem with inflated ratings; for K-dramas anything below a 7 is generally not worth watching, and for C-dramas it seems like most shows below 8 aren't worth the time.