If I had to summarize this manhwa in one word, it'd probably be "trainwreck." You know it's terrible, but you just can't look away. I suppose some would describe it as addictive because you can't put it down, but it's in the worst way possible - this is essentially a melting pot of every confusing Korean drama cliché ever, combined into one story.
You have identical twin sisters with the same name who are unaware of each others' existence but both suffering in equally horrible environments. The only thing that sets them apart is that one is emotionally broken and takes all the hitting lying down, while the louder twin has gone to the other extreme and does all the hitting. On top of this, you have tragic deaths, bullying, mistaken identities that lead to doomed romances, and so on. Doesn't make for fun reading.
What makes it worse is that most of this is introduced within the first volume or two, and since both girls have the same names and virtually the same faces, the reader is permanently confused. I know they're supposed to look exactly the same, but I'm willing to suspend belief in exchange for less of a headache trying to differentiate them. The boys are just as bad; honestly, the only thing that separates the two is that one has marginally neater hair of a slightly lighter colour. Half the time, I'm all the way at the end of a chapter before I realize that I've been reading about Kang Yi, not Seol Kyom. People don't seem to refer to each other by name very often either, so it's just... continuous confusion.
As for the setting, it'd be nice if the manhwaga had actually attempted to establish some! Characters and scenes flit back and forth, changing settings without so much as a panel (or even just a bubble) explaining where exactly we are now. One moment you're reading about Ka Ram mountain hiking, and then on the next page we're suddenly looking at Ka Ram at school... before you realize you're looking at the other twin. I'm not even going to go into detail about the characters themselves, because they're branded by stereotypes and their personalities seem to change at the drop of a hat. Suffice to say that this manhwa is a complete, epic mess - read at your own peril. If you must, at least make sure you have some aspirin.