The only film critic that I know in Vietnam who writes in English and has a background in Screenwriting is Do Thuy Linh. Some of the most insightful articles about Vietnamese cinema are authored by her. Each month she publishes an article on Vietnamese Cinema at Thanh Nien News under a column called Through The Lens. She lives in Hanoi and works as a writer, commentator, and translator for Tuổi Trẻ news and other English language news outlets.
To get a great glimpse into the Vietnamese film industry, you can follow this link to most of her writings:
Make sure to sort Google's search results to show the most recent.