CrowdCity.io may be a cool zombie themed online IO game. You will start by controlling a few of bloodthirsty undead creatures and your goal is to attack living humans to recruit them to your zombie army. Once your group is large enough you'll be able to attack other zombies. Take over each and each city and buy upgrades for your zombies, like speed, life or attack power, and unlock new types units. Kill all of them, eat their brains with CrowdCity.io