Instructions
Start a new zombie game session in "Call of Duty: Black Ops" or resume your current session. For best results, use your knife as much as possible during the early rounds and use the sprint control to make quick escapes. To sprint, click the right analog stick (PS3 and Xbox 360) or press the left "Shift" key (PC).
Buy new weapons if you need them as you see them on the walls throughout the game. Use the mystery box when you find it -- its location is random -- to get random weapons. Always be on the lookout for zombies that drop green-glowing icons when they die; these are power-ups.
Run straight through a power-up when you see it drop to pick it up. A power-up only stays on the ground for thirty seconds after a zombie drops it, so get it as soon as possible. The Max Ammo power-up is an icon of an ammo box with an ammo clip sticking out of it. If possible, reload your weapons before running through the Max Ammo power-up. If you don't, your current clip won't be refilled.