Note, if you want a quick reveiw skip to the last paragraph ;)
The first episode of this anime was really very confusing. After I had finished watching the first eposode I wasn't hooked or interested in the anime at all, I found that I had more questions than I did answers. The second episode was nearly the same, however I began to find things out and I was a little bit interested after watching the second episode. It can't have been untill after the 3rd or 4th episode that I was actually hooked on it. It was a very good story which was very enjoyable, however I found that at the start I was clueless as to what was happening and at the end I got confused about who was dead, who was injured, etc.
The animation was really good, I watched it in HD and I was very pleased with how everything looked, there was nothing glitchy or not to my taste. Arguably there could have been a little bit more gore in some places but personally I was very happy with the level of Animation.
The sound was very good. Wasn't my type of music, however I could see people liking it and I thought that it generally suited the anime so I gave it a ten for those reasons.
Now, when it comes to characters the story got a little bit shaky. I loved the two main characters, and I felt that they were very well explained in the story, so I had no problem with either of them. Thats where it ended with characters really. You don't really get to know any other other characterss very well and while some may have made a quick relationship with some of the less major characters, for me they just weren't on long enough for me to develop any feelings about them.
Overall, I thought the animation and the sound were perfect for the anime and I gave both of them 10/10 because I personally thought they fitted the anime well. However the story, while strong was confusing in places and I didn't really have enough time with most of the character to for any opinion on them.