Read more » Zero Hour is the expansion pack for the computer game Command & Conquer: Generals. Zero Hour added several new abilities and units to each side, and a new mode of play called Generals' Challenge. The extra feature of this game is the Challenges against different Generals. You can select your own general and then have to defeat all other generals using your sources and super weapons. The other feature is campaigns which are similar to the C&C Generals but with different scenarios.