The saddest thing about Woody Allen’s effort to retool his brand of romantic comedy for the youth market isn’t the absence of laughsit’s the bitterness that cuts through everything, which is hardly sweetened by all the Billie Holiday numbers on the sound track. Jason Biggs is a young writer who falls in love with freewheeling actor-singer Christina Ricci (shades of Annie Hall) and who’s saddled with loser agent Danny DeVito (shades of Broadway Danny Rose). Allen plays Biggs’s sour mentor, who goes walking with him in Central Park (allowing us to get two versions of Woody at once), and Stockard Channing does a turn as Ricci’s mother, who also wants to be a singer. The film’s hatred of Ricci and Channing and its affectionate tolerance of the hero’s mousy hypocrisy and his mentor’s negativity are familiar Allen motifs, but the faint echoes of his best work only make this one seem grimmer. 108 min. (JR)