The promise of multimedia is suddenly so exciting that movie people are beginning to forsake the back lots and jump ship for multimedia start-ups. Strauss Zelnick, president and chief operating officer of News Corp’s Twentieth Century Fox Film unit, quit to join Crystal Dynamics Inc, a start-up software company, as president and chief executive. He exchanges 1,200 employees and a division with revenue close to $2,000m for a band of 28 programmers and video game creators at a company in Palo Alto that has yet to introduce a product. Crystal Dynamics, one year old, and backed by established Silicon Valley venture capitalists, is devising games for the next generation 32-bit systems.