Story: 6
You read the synopsis just as well as I so you should sort've know what you're in for. The storytelling, albeit fast-paced, is actually written decently in my opinion. While each mystery was fun to solve in it's own right (fan of the mystery genre), until the later half of the series, they are all somewhat predictable; effectively causing the reveals to be little more than explanations for those who couldn't figure it out. All in all, as a mystery piece is wasn't too bad and as a story overall, I believe you'll be drawn to it if you stick around for episode 5+.
Art: 7
Long story short, the art was better than average and aside from the pointy chins, as others have pointed out, it was well animated and had some very nice sequences towards the finale.
Sound: 8
So the soundtrack, which for me consisted of the opening theme, ending theme, and the climax theme (Spanish flamenco as one user put it), was well done. I'm a huge fan of the ending theme for being catchy despite my american tongue falling over the lyrics to it. As for the climax theme, the little tune was literally my favorite part of the show and the only part i paid attention to during the first few episodes. Again, all in all, wonderfully scored.
Character: 5
Simplified and to the point, aside from Inga and Kazamori, the rest of the characters were either bland with no development or developed into something cliche. Without providing spoilers, most are very cliche in their roles for the plot and aside from the last 3 episodes I was very bored with their development as a whole. Despite that last sentence, I found nearly everyone of them like-able in their respective roles.
Enjoyment: 7
As you can tell so far ( at least I hope), despite how the review came off, I thoroughly enjoyed this series. It captivated me with its music, intriguing way of spinning the stories each episode was based off of and overall telling of the conflict between the searching of necessary truth and the telling of necessary lies.
So overall the show gets a 6.6 from me, which rounds to a 7 here. Give it a chance. You just may find yourself captivated by the more underlying themes I failed to mention in this review! :P
