Oh, Rosalind Russell, you died too soon. If only the actress were alive today to catch David Olsen better the actress in his turn as Sylvia St. Croix in Arizona Onstage Production's delicious "Ruthless! The Musical." Russell would have groaned. She would have winced. She would have gasped. But most of all, she would have laughed, applauded and maybe learned a thing or two from him. Olsen is just one of the delights in this musical spoof full of ruthless characterizations designed to do nothing but entertain. Outrageously entertain. Olsen, long-legged, high-heeled, and in a jet-black wig and chic/tawdry dresses, camped it up as he flung his long arms around, caressed the audience with his throaty Shakespearean voice and out-did the most dramatic drama queens. Come to think of it, just about every character out-did the most dramatic drama queens in this production, directed with a flamboyant sensibility by Kevin Johnson. There was little Jalyn Wheatley as Tina Denmark, an 8-year-old mixture of Patty McCormack in "The Bad Seed" and Shirley Temple in any number of flicks. Tina wants to be a star, and she'll kill to become one. Literally. Wheatley, achingly saccharin one moment, murderously evil the next, nailed the character. Her Donna Reed-esque mother, Judy Denmark, loves being the mom to such an accomplished talent, but isn't sure she approves of Tina killing the lead in the grade school production of "Pippi in Tahiti: the Musical" so that young Tina can take over. Stephanie Sikes' Judy was a stitch. In true Stepford Wives style, she was robotic and dim-witted as the mother. Later, transformed into a big Broadway star, she was conniving and about as murderous as her daughter. Diane Thomas had a supporting role as a ruthless theater critic, Lita Encore, and her Ethel Merman turn, accentuated by a sublimely bad red wig and an impressive belter's voice, was fall-over funny. Rounding out the cast and keeping the laughs bubbling over were Liz Cracciolo- Redman and Sarah Spigelman. "Ruthless! The Musical" was an off-Broadway hit in 1992. Critics and audiences loved its campiness and its take-no-prisoners approach to spoofing such classics as "Gypsy," "All About Eve," "The Bad Seed" and any number of other movies and plays. Arizona Onstage Productions, a gutsy company that brought us the impressive "Assassins" last summer, taps into some little-known talent in our city to produce irresistible theater. At the Thursday night preview, there were a few tech miscues, and the band sometimes drowned out the singers. Nevertheless, the production had audiences roaring throughout, and on their feet at the end. The first act, which sets up Sylvia St. Croix's desire to mentor little Tina, awakens Judy's desire to be a star and Tina's ruthlessness on the road to a life of fame on stage, is the funniest and most successful. The second act, which finds Tina locked away for the murder of her classmate, and her mom in a New York penthouse playing the ultimate diva, doesn't work as well. It lacked the motivation and pay-off that the first act had, and so some of the air is sucked out of the humor. That aside, this play is designed to lure theater lovers and novices in with a confoundingly campy - and ruthless - take on old movies and plays and the people who were in them. And that it did. Rosalind Russell, we're sure, would have been most pleased.