From what I've seen so far, there's nothing really "wrong" with this series so far. It isn't "bad", per say, but there's just nothing overly special or truly interesting about it. That kind of sums up this episode in a nutshell. Not bad, but VERY paint-by-the-numbers. The evil bad guy with his exotic island lair who escapes by literally shouting "get the chopper! Now!" (somewhere Arnold is cheering) and who has the hero cold until feeling the seemingly compulsive need to explain his dastardly plan (seriously, Skye is only alive because of plot luck. Anyone who has ever fired a gun knows that it is a distance weapon. It's not just Agents of Shield that does this of course, but every time I see a villain walk up to the hero and put a gun in her/his face, it makes me roll my eyes), before everything starts exploding was pretty standard.
I thought Coulson was solid, once again. He's the best part of the show so far for me, but I still stand by what I said in the discussion of last episode. He really feels like a strong supporting character, not a lead. I have a feeling they're going to try and develop Ward and Skye into the ones to carry the show, with Coulson moving into a more ancillary role (kind of like what they did with James Caan and Josh Duhamal in Las Vegas), but I'm not sure if Ward has the character strength to pull it off. The things they're introducing to make him cool just are not working for me. He feels like a poor-man's rip-off of Steve McGarrett from the rebooted Hawaii Five-O, and not half as cool.
May's character does nothing for me. She seems like a very strong candidate to be an early kill-off. We're only three episodes in and they've already kind of dropped the hints about her mysterious background. The highlight of the episode involving her was Coulson essentially telling her to give the complaining a rest with his Avengers line.
The ending was neat. The scientist Hall is the Marvel Comics villain Graviton, who I never thought they'd do on a screen of any kind but who I quite like in the comics. I thought the actor portraying him did a solid job. I liked his final few scenes with Coulson.
I think a big, big problem this series is suffering from so far is the fact that it's the de facto television legacy of The Avengers movies and Joss Whedon. If I didn't know any of the prelude to the series, I probably wouldn't think it's bad at all. But knowing that it comes from the creative parentage of all the Marvel movies (which, Iron Man 2 notwithstanding, were amazing) and the guy who brought Buffy, Angel and Firefly to life, it's difficult not to have big hopes. And so far, they just haven't been realized.