One game session can last up to one hour, during which players can roam freely over huge maps, completing randomized objectives and dealing with random events. 
The goal is to try to survive and conquer by any means necessary. Get stronger every time. Level up to unlock new weapons and abilities. Try to survive the storm.

Minimal requirements:
 

Processor: 3.0 GHz Intel i5

Graphics: ATI Radeon HD 3800 / Nvidia GeForce 9600 GT

Memory: 2 GB RAM

Disk space: 1 GB

System: Windows 7