Elfen Lied can be compared to eating a really greasy and fatty meal, it's delicious and very enjoyable while eating it, but afterwards, when it goes straight to your thighs, you'll reflect on it and ask yourself "was it really worth it?".
While famous for its gore and nudity, it's not anything that you haven't seen before if you've watched a lot of Western cinema or played a lot of Western games, and because many reviews are built around its approach to violence and nudity, many dodge the question as to why the show can be called as terrible, and why it can be called as fantastic.
The answer to the former is very simple: the story. I tried to love the story, I really did, but the plot conveniences just drag it down too much, namely, convenient amnesia. Seriously, the two main characters suffer from the worst plot-convenient amnesia I have ever seen in story telling, I would've been happy with even the worst attempt with an explanation but they could only bother with amnesia? I hate to bash this show so much because I really did enjoy it, and here's why;
The characters, excluding the plot-convenient amnesia, are well developed, and their backstories are the saving grace for this series. Each episode hints at more character development for the main two characters and it does make for a thoroughly enjoyable experience, but don't fool yourself, at the end of the day, this is a romance anime.
The metaphors and overall theme of the show have been called a commentary on humanity and the morality of murder for the sake of survival and while I don't believe it succeeds in doing something so accurate as a 'commentary', it certainly has a unique approach to the values of human life, and if romance isn't your thing, then it's worth the watch for that approach alone.
The art and music are fine, industry standard. But for the music nuts out there like myself, the main theme tune is a real beauty that just gets overplayed that bit too much, making it more of a chore to listen to in contrast to the delight that it is to listen to in the earlier stages of the show.
Overall you'll most likely enjoy Elfen Lied if you don't over analyse it, it's just best to turn a blind eye to the whole "oh man good thing I got my memory back now", you'll enjoy it far more that way, trust me.
