Hey all found a nice and simple way of doing the 10,000 zombie challange in a short ammout of time. Called Dead Driving which currently has 52days left to complete. To do this you need to have the first combo vechial which is the Turret Rig. Once you have this the challange is simple to do and you can rack up your kills easily. The way I did it was to find a area of the map your used to and that you can easily drive around like a block of road and memorise the route. Now all you need to do is simply get in your truck and blast away racking up 10,000 kills very fast. It took me just over 9mins to do and you get a fev cheevos along the way also. Watch the video the below to see how I do it http://www.youtube.com/watch?v=l0LzsNYbg9g&feature=youtu.be