Undead Labs has just released the first in-game footage of Class3, their zombie game that is powered by Crytek’s CryEngine 3. This video is basically a “motion screenshot” that illustrates the game’s day/night cycle. Class3 promises to be a true zombie survival game where food, water, shelter, and ammo will be essential for your survival. The game will be an open sandbox world that develops in real-time, dynamically generating content based on your actions, the choices you make, and the ever-increasing zombie threat. Enjoy the video after the jump.