Zombies eat brains and other human parts, whereas regular food gives them nothing. Watch the conveyor attentively and click on the part that zombies like. Activate special abilities and increase the amount of points.
You are in the zombie lab and it's the weirdest place you have ever seen. Your mission is simple and all you have to do is fill the zombie meter by clicking on the right foot at the conveyor. Zombies eat only flesh, so avoid clicking on hamburgers, spaghetti's and other food. Fill the meter and activate special abilities, that help you during the mission.