From the directory listing:
With the surface world overrun by robots, the rabbits remain far below, their underground world a safe haven from the rule of the robots up above. You have the task of building a new home for the rabbits, keeping them entertained and rested as they work, and digging ever downward to build a new rabbit empire and rediscover ancient rabbit secrets.
brought to you with love from Breakdesign.
World of Rabbit' is a resource management game. The tutorial will help you get you building rooms for growing food and powering your burrow. You'll also need some dormitories for your rabbits to sleep, and some entertainment to keep their spirits high as you dig ever downwards, uncovering secret rooms and lost powers.
The Burrow will continue to be active even when it is not a foreground task on your handset - I suspect that it simulates the time that has passed when you switch back to the application, rather than it running constantly in the background, but the end result is the same. A living, breathing, colony of rabbits inside your phone that you need to manage and take care of. How far will you be able to extend the burrow?
'The Dig' is a free download both from the Windows Marketplace and the AAWP App Directory.