I really liked the way things turned out with the "gang" - I wasn't expecting anything along those lines before the old woman showed up in the middle of the stand-off. The attack on the camp was where I was expecting the season to end and I'm glad to have been wrong, because I didn't want to wait for season two to see reactions from the survivors. Even knowing it was coming at some point, that attack was damned brutal. I also liked the symmetry between opening the episode with Andrea and Amy on the lake, and ending the episode with them as well.
"Vatos," by the way, was written by Robert Kirkman himself, the creator of the comics series.