Sandra Bullock does a pretty good job of playing Gwen the drunken party girl who gets herself into trouble. She is not gung ho for a treatment center, but her other option is jail. Actually, I was not sure how she avoided jail at all, and 28 days seemed too short a time for all the hilarity, action and breakthroughs in this film, but other than these things, I was really impressed with Bullock and the ensemble acting - the balance of comedy and drama. The one actor I thought over-acted was in the character of Gwen's boyfriend. He was too much, and it was a relief to see him off the screen. Viggo Mortensen is endearing as the other guy for Gwen. I would like to have seen more of them together. I think people will love the soap opera gags and the send-up of drug/alcohol treatment centers, but will also get the serious nature of the interactions in the "chemistry" among all the characters in treatment in the film.