There are subtle clues as to what is going on in the plot and if you don't pay attention, you aren't going to get it until they really begin to explain whats going on. (Which they haven't really, they just elude to everything and seem to think [or hope] you'll get it.) The plot isn't very clear so far, but as the story progresses there should be a decent climax.
The black rider isn't given a real cool, elaborate costume. The characters' hair is done in that lumped-up 10 line bit instead of complex lines where you can see different layers where they should be, how the hair lines back for a ponytail, etc. The art may be simplistic as far as character design goes, but I think that for a story that has so much going on the art makes it a bit easier to understand. The clean lines make it easier for the story to develop via dialogue.
Many of the characters seem rather one-dimensional. Stalker girl just keeps going and going after Seiji, Izayu is crazy as sin, and our main man is just a normal high school student with dreams of something more. Hopefully as the story continues there will be more of an obvious growth for the character, but it doesn't look like it will happen any time soon.
Somehow I found myself pretty entertained by this, even though its flaws are very apparent. If you have time to kill and find yourself reading Durarara!!, be prepared to be left with a "WTF did I just read?!" feeling.
