TLDR: Slow first episode, but enjoyed the rest.
At first I wasn't impressed. I watched the first episode and the apparent slow pace made me lose interest.
But several months later I continued with the 2nd episode, which is when the murder actually happens. By the end of the the 2nd episode I was hooked and watched the rest of the episodes in a day.
This is now one my top 10 favourite manga/anime ever, along with Higurashi, Death Note and Liar Game.
I won't talk about the plot other than that it's primarily a locked room murder mystery. I recommend going into this series blind. By the end of the 2nd episode you should be able to decide for yourself whether to keep watching or not. Personally I loved all the red herrings and twists. There's enough clues for you to guess the truth before the big reveal.
I will however talk about the art. The only way I can describe it is "smoooooth". The animations are fluid and there are so many backgrounds and angles used. Unlike most of the popular shounen anime these days, every scene looks brand new and I don't see many assets reused. The character's movements flow from scene to scene, and their actions all carry a unique flair. For example, in one scene the male protagonist is waving his cigarette in the air in a dimly lit room, and the way the light trails his movements is beautiful.
