Sierra Entertainment today announced that Barry Pepper (Flags of Our Fathers, The Green Mile, Saving Private Ryan), Gordon Clap (NYPD Blue, Rules of Engagement) and Paul Guilfoyle (CSI, L.A. Confidential) have joined the cast recording the voices for PROTOTYPE. This is a completely new kind of open-world game which tells the story of Alex Mercer, a man haunted by his past, fighting a secret war in New York City. As the action spirals out of control, a conspiracy tied to his origins threatens the future of mankind itself. Mercer's amazing shapeshifting powers allow him to become an exact replica and steal the skills or powers of anyone who crosses his path. PROTOTYPE will be available this summer, for PC, Xbox 360 and PS3.