I saw this way before I saw Elfen Lied, and both were only a few years ago, funny enough. :?
I never bothered to get into it because the few fans I knew that liked it were kind of twisted and I didn't know what to make of the content... I never knew that Elfen Lied was actually a really dramatic, interesting work of art. :? The anime is too short though and I heard the manga is better... One day I may be motivated to finish it but for now I only saw 4 chapters and pretty much the same content (I heard there's at least a different ending and some character named The Unknown Man.)
As for the flash itself, it seems pretty dark, disturbing, and dramatic itself. :? Other than the atmosphere though, I'd agree it's completely different than Elfen Lied. Elfen Lied was more Sci-Fi Horror along with a character whose like many bullied outcasts, but one who turns their sorrow into hatred and goes along through life killing people, which is sad. :(
This however seems more like the classic Deal with the Devil type of stories, but with some fairy tail like poetry. I find it pretty cool. :)
I can't tell if Lillium should be sympathetic or not with going through something so brutal like killing her seemingly innocent family, although she did seem to regret it at the end... but how come she wanted to be friends with an evil shadow? Did she not know it was evil and/or she was that lonely?
I'm surprised to see this as the most highest rated M-rated Drama movie though and a Newgrounds Classic, I wish I saw it a long time ago. :( Heck, she's even the person in charge of the Art Studio in Pico Sim Date <3 or whatever. XD
Finally, the gothic, dramatic opening song really gets to me... I'm not sure what to feel from it, but people on youtube said it's one of those few songs that make one think of a funeral and remind them of their lost loved ones. :(
I wonder what's going to happen to her now...