Interesting, suspenseful flick, with some great direction, hampered by terrible acting and atrocious dialogue. The overall concept is an intriguing one, and could have made for a better film in the hands of a competent writer, but instead the screenplay is filled with idiotic characters and ludicrous dialogue. Combined with some terrible overacting by most of the cast, and the dialogue-heavy scenes become painful to watch. Fortunately, the 'action' sequences redeem the film, as they are shot well and become incredibly suspenseful - especially the scene with the quiet room. Some great gore effects and a fitting ambiguous ending make it a worthwhile viewing.