To appreciate 28 Days , it's best to be thankful that director Betty Thomas hasn't forced Sandra Bullock into a remake of Clean and Sober . Instead Thomas has balanced her comedic sensibility (evident in Dr. Dolittle and Private Parts ) with the seriousness of alcoholism and substance abuse, and she succeeds without compromising the gravity of the subject matter. Some critics have scoffed at the movie's breezy, formulaic portrait of 27-year-old boozer and … mehrpill-popper Gwen Cummings (Bullock), but this smooth-running star vehicle does for Bullock what Erin Brockovich did for Julia Roberts, focusing her appeal in a substantial role without taxing the limits of her talent. It's no wonder that Susannah Grant (who wrote both films) was one of the hottest new screenwriters of 1999. She writes "Hollywood Lite" without insulting anyone's intelligence. As played by Bullock, Gwen is an alcoholic in denial whose latest bender with boozer boyfriend Jasper (Dominic West) ruins the wedding of her sister (Elizabeth Perkins) and lands her in a month-long rehab program with the requisite gang of struggling drunks and junkies. Newcomer Alan Tudyk steals his scenes as a gay German rehabber who might've dropped in from a Berlin performance-art exhibit, and Steve Buscemi aptly conveys the weary commitment of a counselor who's seen it all. Thomas has surrounded Bullock with a sharp ensemble, and the addition of singer-songwriter Loudon Wainwright III (as a kind of Greek chorus crooner) is sublimely inspired. Certainly no surprises here--the warring sisters will reconcile, and at least one rehabber will fail to recover--but there's ample pleasure to be found in Bullock's finely tuned performance, and in Thomas's inclusion of flashbacks and tangents that add depth and laughter in just the right dosage. --Jeff Shannon weniger