It's good, but it could be so much better. They have shorted a (big?) part of the manga. It's a pity! More development equals more attachments...
It would have needed more episodes, but some scenes are striking and will definitely make an impact to the viewer, for sure, and the OST is beautiful, but like I said, we needed more episodes, and we feel that it's going too fast, and it remains a significant defect!