VERY similar to Elfen Lied. In fact, one of the only animes I've found to be comparable to the quality of Elfen Lied. Both have very deep psychological roots, both can be dark, and both may take more that one watch to completely understand.
Complex and psychological storylines, dark and distubing plots, characters with great depth aswell as awesome music to accompany it!
At first this may seem like an odd recommendation. But the two series have more in common than you think. Both of them are very much so psychological animes, each dealing with people and their emotions, how it effects others, etc. A prime example of the psychological similarities is an underlying theme of the inability to make and sustain relationships in both of these fine anime.
Beginning both have gory scenes. Elfen Lied at first look, seems more gory, and in reality it is.
While some of this scenes (of both animes) will not touch you, some does, and much.
Elfen Lied story is much more simpler than NGE. However it may not look as that at first.
Both are also highly psychological. With NGE winning this point.
Loved the Elfen Lied art. Both also seem have some unique characters and are well explored. Also both have a nice mix of Action and feelings.
Ending, both leading female characters are sexy. :)
Both are dark anime's, though depending on your interpretation of "dark" you may not not love it, Neon Genesis is more psychological than Elfen Lied but as far as dark goes Elfen Lied takes the cake.
Both are character studies centering around emotionally and mentally troubled people and in both cases, the actual plot of the series is only used to further character development and pretty much ignored asside from that. However, while Elfen Lied executed itself with mastery, I believe Evangelion was too blatant in its overall message, espacially towards the end.
The psychological aspects make for a similar experience. The character development in both are very good and uncover major issues and the plot advancement is somewhat similar in feeling (can't really explain that, though).
Both are very psychological. They both deal with growing up and feelings of loneliness/alienation/abandonment. Both have characters that want to "evolve" mankind. Both have organisations experimenting on living creatures to suit their own goals. They also both show the power of love and compassion, and connecting to other people. There's alot of character growth in both series.
Both is a fascinating anime's...
It grabs onto the viewers attention from the 1st episode.....
Both has MOST AWESOME OP's of all time
Both have very deep psychological roots
Lots of action, gore, screams....
Recommended to anyone who likes fast paced shows....
Both have nice concepts.
Both have traumatized children.
Both have mentally challenged characters.
Both are overrated af.
Both have supernatural elements.
These series both have complex and dark story involving mysterious organization aiming to change the world and humanity.
In addition they involve some quality action.