The more mature/ dark/ graphic approach was great, and some of the ideas were interesting- certainly a lot to take in. The writing and acting had its moments on both ends.
Future Peter was okay, but played up the deus ex machina a bit much.
Nathan... Well, I expected him to come back with the blood from Adam, then when I saw Peter's hand on his head I thought, maybe Peter'd use Linderman's powers (unintentially)... The hallucination thing, Niki/ Tracey thing and decision thing were good, but the God thing was a little too 4400.
Claire was pretty good as usual. Not sure about the chosen one thing.
Sylar... Awesome. Seemed like he wasn't working as well as he's capable of with his powers at times, but I guess he was just trying to enjoy the Claire part and experiment with the healing part.
Elle... Excellent.
Tracey... Interesting. I always liked Niki, and Larter was one of the better actors in season 1, not sure about this. I really hope it's a different person and not another personality though, giving her another power is just silly.
Mohinder... Too out of character. I know, abilities would make someone act different, but it went too far, they gave him too much and it came out all messy.
Maya... fits in better now, still not quite right though.
Angela... Most interesting character of the opening so far. Shocker at the end was kind of awkward though.
Hiro/ Ando/ whatsherface... I like the idea of their friendship being put to the test like that, and Ando with powers actually worked and he's an interesting character. Couldn't stand the speedster though- felt like Charmed/ Cleo 2525/ Farscape or something. Also it's really annoying how they talked about Batman and Robin- Star Trek I can accept, but they'd probably have barely heard of Batman aside from the movies, just felt too much of a reference.
New villains... Hm. Interesting, kind of annoying especially having not read the comics. Great to see Weevil from Veronica Mars as Jesse/ Peter though.