I think this anime was great.
The story was avesome with many surprises and some twists.
And even though it was a very dark and evil plot it also had love and friendship (but mostly evil).
the music was also very good and fitted in. The opening theme fitted perfectly with the story.
The dialogues were good but could have been better, some times the voice didn't fit the feeling of the character.
Animation. Beautiful.... only strange part is Diclonius doesn't seem to bleed when legs are missing but a normal cut will bleed like on a human.
Anuway if you are not afraid to see blood and torture, watch it! you won't regret it