plant alot it depends on what level ur at
It is best that you have BLUE zombies. It will be easier to beat corporateville.
Unless you are on level 16 and above, you can't attack Corporateville. Sorry:(
The one in zombie farm
At level 21
There are 5 different kinds. You'll unlock them on level 4, 8, 15, and 25.
Level up
you need a blue gravestone.
you buy it with real money. to buy it you go on choose your farmer and tap the king zombie head and it will take you to the app store so you can but it.
You have to find 3 Rusty Fragments, found randomly after invasions.
Certain invasions unlock certain abilitys. While invading an icon will pop up, to activate the ability click the icon
You have to reach Lv. 36 (you'll need to get a total of at least 97,000 exp).
level up (it says the level + you need to be in barckets next to te name of the level)