I never call something a "masterpiece" but if I did, then it would be "Beyond Evil". while I was watching I had sleepless nights, as my theories would not let me go, and afterwards I even looked for the soundtrack.
The awards are certainly well deserved. The acting, the soundtrack, the cinematography, everything served to enhance an already incredible story.

Here are some aspects that impressed me:
* The whole drama is not something to watch casually. Every minute is relevant, every twitch or facial twist is an important part of the story.
* I loved how I got to see only bits and pieces of what happened -- and had me mistrusting everybody throughout the series. Especially during the first episodes, which left me reeling with their cliffhangers. And then there was some new bit of info which slotted seamlessly into what I knew but changed all my ideas on what was going on.
* The first episodes made me guess and mistrust to the point where I expected a new twist even to the very end, when in other dramas I would already have been bored by the predictable plot -- I did no longer trust my own deductions nor my knowledge of the genre's usual plots, culprits and tropes.

* Every character is just shades of grey. Everybody's got their motives and reasons for their actions. Nobody is purely good, and still, a lot of them are somewhat likeable. That is something not a lot of dramas manage to do.
* I loved the role smiling and laughing played in this drama. I think the times when a smile, a chuckle or a laugh was really genuine instead of expressing any kind of negative emotion could be counted on the fingers of one hand.
* While the female characters were in the minority (no surprise there), all of them were strong, independent and active characters in their own right. (Apart from the victims of the serial killer, which was one of the few genre-conforming elements.)
* And last: No romance! Always a plus.

If you are a fan of mystery thrillers, this one will be worth your time!