Elfen Lied is unapologetically brutal in its execution, which will be made apparent to any viewer within the first few blood-filled minutes of the series. Aside from the gratuitious amounts of gore, however, Elfen Lied still delivers a very heavy and emotionally taxing story. Elfen Lied was rather challenging to watch - not just emotionally, but also intellectually, given the highly dubious nature of the Diclonius. The Diclonius are a crucial part of the anime and are undoubtedly the driving force behind the plot. The anime is not terribly original, but still very well executed, and concisely so, managing to fit a captivating story into 13 episodes.
Yes, there is lots of gore, which I think is a nice addition and does well to establish a unique (or perhaps notorious) identity for the anime. There also seems to be a lot of fan service and ecchi moments sprinkled throughout the anime. While some may find this disagreeable, I find neither particularly annoying and they really do nothing to sway my opinion of the anime in either direction.
Elfen Lied's plot is very much character driven, as the histories of the Diclonius are gradually unravelled, and with them, their relationships to the main characters and a handful of dark secrets held by Kouta. The story does carry a lot of emotional baggage and these heavy, dramatic moments are what make the story captivating. A couple of side plots are interweaved into the main story, which do their job of developing the characters and fleshing out their backgrounds a little further. However, the story seems a bit muddled at times with all of the subplots of the main characters competing for the spotlight.
However, being a character-driven plot, I feel the main story of the Diclonius about to unleash all hell upon mankind is left unattended, and some loose ends were not adequately tied up at the end of the series. That being said, the main story itself is not particularly original nor exceptional, and neither are the angsty stories behind each character.
While the basic premises behind the story are not particularly fresh, the addition of the Diclonius is an interesting and unique spin, and the story as a whole is still wonderfully executed and very moving.
What really makes this anime shine is the unique character design of the Diclonius. In one moment they are ruthlessly barbaric, tearing dozens of humans apart with no hesitation or remorse, and in the next childlike and innocent in their demeanour. The two-faced nature of the Diclonius manages to set up a number of dramatic and emotionally charged dilemmas which are the main impetus of the entire series. Lucy's split personality is an excellent plot device which left me craving for more elaboration and made room for conflict between parties throughout the series. It is this duality which makes the story so compelling - some scenes can make you cringe at the utter lack of conscience and morality of the Diclonius, while others make you pity their tragic existence. I was left conflicted at times, unable to make heads or tails of what to think of the Diclonius, which is why I think they do a great service to the anime. The character development of the Diclonius and the main story go hand in hand here.
However, while the backgrounds of the other main characters are adequately touched upon and well developed, they are not particularly compelling, nor do they stand out as very unique. I do have to admit that Bando was a well executed character though, due in part to his superb voice acting.
While the scenes of gore are rather fluently animated, unfortunately little can be said of other scenes throughout the series. The visuals are quite nice, and while not exceptional, have a few beautifully drawn scenes here and there.
Lilium, the main theme throughout the anime, is used to great effect, and is itself a beautifully haunting melody well suited for the anime's subject matter. The other tracks throughout the series also manage to create a suitable atmosphere for each episode. Sound effects are quite alright and do their job. The voice acting of Bando stood out quite well and did much to establish his character.