Z Day is a free Android game developed by Pi Game. It falls under the category of strategy games and is set in a post-apocalyptic world overrun by zombies. The game challenges you to collect resources, fight zombies, and build a base to survive the apocalypse.

In Z Day, you start by gathering resources such as food, water, and building materials. As you progress, you'll encounter zombies that you must fight off to protect your base. You can recruit survivors to help you in your fight against the undead and upgrade your base to make it stronger.

The game has an intuitive interface that makes it easy to navigate. The graphics are decent, and the gameplay is engaging. Overall, Z Day is a fun and challenging game that will keep you entertained for hours.