This a single player mission I recently Created. The goal is to escape the city in the helicopter. When you turn on the helicopter at the end you have a minute or so to fight off waves of zombies until its ready to take off.

I modified the AI to turn them into zombies and created the horde mode.

All Created in Unreal Engine 4.

Geo from: https://www.unrealengine.com/marketplace/zh-CN/slug/middle-east
Zombie Geo: https://www.unrealengine.com/marketplace/zh-CN/slug/zombie-with-t-shirt
Base gameplay from: https://www.unrealengine.com/marketplace/zh-CN/slug/third-person-shooter-kit