• Get 1 gold for each human you kill and compete against other doctors in the world for the top score. The higher you rank, the more rewards you receive up to 200 Gems and 5 Mega Lotto Tickets for 1st place.
• Since all mad scientists want the same thing, participate in the cooperative events often. Get rewards by taking part in the senseless slaughter of humans or by building up and creating a new zombie utopia with all of your other fellow Zombie Doctors.
• Most 4-6 Star zombies have a special skill that they use to create more zombies or destroy humanity. Level those zombies up to 2 with gold for cheap. When you get a duplicate zombie, you can bypass the huge cost to level up to 3 by sacrificing that zombie.
• Not only do they get much needed pills to feed their zombies, but you also get 20 Friendship Points (to a max of 200 a day). 50 Friendship Points can be turned in to get a Virus which will permanently boost your zombies’ levels. So give out pills and level up as often as you can.
• When you’re defending your home base in Endless Mode, the humans only appear out of the corners of the building. Take advantage of this and place your top level zombies right where the zombies appear. This will quickly build up your zombie numbers for the tough boss fights ahead.