The more people the better. If you are alone, you need to rely on your towers a little bit more. Design your maze so it has the longest possible route. You should have towers that have a very large range, Violators and Mortars are good. Drones are also good, having several of those set up can allow the drones to follow him a great deal through the maze. Use slow fields to make sure your pump him up with as much lead as possible, and use amps in strategic points to make sure that when he is on that amp, the maximum amount of towers can hit him. The Tesla gun has the highest rate of fire, so using that on the amps would be good. Using the slow gun (I forget what its really called) to freeze him over the amp will significantly improve damage output. There may be better ways, but I've been able to beat him every time with this method. Remember, over all, protect the jaffa cakes!