Since you have given zombies the ability to efficiently carry and use guns why not make a sequel where we control the zombie? Perhaps invade cities to infect humans to gain supporters.
If you need a little help on getting first place on the last race, this is the method I used. First off make sure you have all upgrades.At the start of the race insult all the other racers, and follow up with a sprint,as you are running ahead of everyone commando the fool in first place, this should earn you first, and a some distance from the rest of the racers.Every time the judges show there mugs call in a holiday,and remember to sprint, and insult every chance you get, and in the situation that a fool is able to get close to you knife him.
If you do all of this you should marathon pro for a win.
Rosey your save data is saved on cookies that are located with your internet browser. If you clear all your history (including the cookies) all your saved games files will be deleted.
I believe the last badge should be "Beat the game on any difficulty". For the amount of time that it takes in order to achieve said badge, it more then compensates for the lower difficulty of beating the game on easy.
Of course there is a badge for only getting 50% of the game completed. If your data is continuously being deleted, a 132% badge would be out of the question.