The city has been bombarded by zombies and you have to get your tail in there and save all the people you can. Do NOT let the zombies eat the brains of anyone. Squish as many of them as you can. You have to stop by the people to pick them up and drop them off at the safe zone. Use the arrow keys to move your taxi around the city and use the space bar for the handbrake. As you get more people, you will earn cash and you can upgrade your vehicle. Get out there and save those people before they become brain food.