Watched the mid season finale. Like some have said, I wasn't that impressed, I think I like a few other episodes better this half the season.
But that being said, I think it did a nice job on setting up a good half season in introducing some new characters, putting question marks on some old, and also, shifting the story from the most dangerous things from being walkers to other groups of survivors.
My guess is Rick and crew go back to save Daryl and Meryl (sp?), that is why you see the smoke and the Gov looking around, and why Glenn is mad saying "why did you bring him here". Rick is going to redeem himself from leaving Meryl behind and coming back too late in the first season.