No one have a clue on what happened as the whole world is now filled with zombies. Somehow, it just happened overnight when no one was prepared. Now, the survivors need to escape the city since there are too much zombies for them to handle. Reports said each time a zombie kills someone, the latter turns into another one of them. You can only kill a zombie once you destroyed their brains or something like that. You, on the other hand live in a small town, where only a few people live. And that is your advantage since there will be less zombies. You are fortunate enough to have a tractor that you can use to flow those zombies on the road.
The idea here is to drive the tractor to the finish line. Flow as much zombies as you can to lessen their numbers. You will definitely get more points from that, but that won't determine how much you will be earning. You can use your earning to buy some upgrades for your tractor. There are no time restriction in the game. You will start from the last checkpoint if you die after the checkpoint. The game will be harder as you make some progress.