You get to drive a free roam monster truck around a custom built city hunting/splattering zombies with a 3 minute time limit.
If you can't find and kill all the zombies in that time, there will be a nuclear strike to destroy everything.

I uploaded it about an hour ago. You can easily find it with my gamertag AGlT0 ( I = L and 0 = number 0 )
Its like a new game. Do try it out, share it to your friends, promote it anywhere, and send feedback to me here or in xbox live if you have any.