I dunno if I would say the show got darker either, it just came to its logical conclusion. I can't point to many episodes even early on that were all sweetness and light, even the synchronised dance fighting one had its darkish and kinda creepy twist.
I think there's a definite downward spiral to be found in the show's atmosphere. For a few episodes after Asuka's arrival, it seems like Shinji might break out of his shell a little and things show signs of working out for everyone, but then everything kind of implodes. In fact, I'd say it divides pretty neatly into four distinct, successive moods: bad, better, bad, worse.
Really, the "logical conclusions" of Eva
were always intended to be dark. Its a deconstruction of 1980's and 90's super robits anime cliche's. What else would you expect, given the various shades of triumph most of those shows had?
Would you believe EoE was the first time I ever saw or even heard of Evangelion? They played it on HBO years back at night.
I had no idea what was going on but it seemed really great. :V
I get the impression that's a pretty common way of getting into the show. People see EoE and want to know WTF they just saw, so they go and watch the series from the start. Even if you don't quite follow along with the movie, it's a pretty intense and memorable experience, I think.
A friend of mine tried to introduce me to the Eva
that way. I was confused.
But seriously, at the time I didn't really think about anime as a separate thing from western animation (oh, and my friend only brought the subtitled version. Yay?) and it was years until I bothered finding out what the fuck I watched that night. I didn't regret it, though that's partially because it introduced me to other, less obtuse anime.