While , like I said, I'm a little uncomfortable with Cersei's portrayal in the show ( in the books she's angry, crazy and paranoid while in the show she's calm and rational ) the actress does an wonderful job with the role they give her.
Tywin exchange of looks with Arya was great, that was the best thing of the episode, I didn't see Tywin smile.Harrenhal feels quite different compared to the books, but the storyline there is really great, the only thing that I didn't like there was the name chosen, The Tickler's scene in ASOS is one of the best of the whole series.I enjoyed Theon and Bran too.
Thing with Tywin is, I don't know, he behaves differently than in the books. In the show he looks a lot more lively. In the books he never raises his voice or something like that, while he does it in several occasions in the show.