Elfen Lied is a beautiful anime with action packed sequences from the get-go but isn't your plain over the top action driven anime. There is definitely an underline story about what it means to be human, true friendship, and love.
We are introduce to Lucy early on and immediately are told two things about her. Her powers are beyond that of a regular humans and she is a cold-blooded killer with no remorse.
As the story progresses we learn that things are little more - complex. As Lucy after injuries is found by Koda and his cousin they take in Lucy and the series takes on an almost slice of life feel to it. Delving more into the relationship between characters who are completely oblivious to Lucy's true nature.
There are moments of gratuitous nudity for no purpose other than to have it which I found tasteless. But there are times of extreme storytelling to try and convey the pain each character has lived through. So there is a balance of sorts. All in all it is a really good anime worth watching and at only 14 episodes makes for a good binge watch.