Airstrike (area of effect fire support):
This skill tree will earn you the capacity to call in Air support. It is quite helpful especially when in a pinch, while dealing with a large cluster of Zombies.
Airstrike
(Unlocks Airstrike Button)
Call in the Air Force to conduct a massive airstrike, when threatened by exceptionally large groups of Zombies.
Damage 1000
(Aistrike Passive Upgrade)
Airstrike damage increases from 500 to 1000.
Damage 1500
(Aistrike Passive Upgrade)
Airstrike damage increases from 1000 to 1500.
Damage 2000
(Aistrike Passive Upgrade)
Airstrike damage increases from 1500 to 2000.
Airstrike -20%
(Aistrike Passive Upgrade)
The cost of every airstrike will drop by 20%.
Airstrike -40%
(Aistrike Passive Upgrade)
The cost of every airstrike will drop by 40%.
Airstrike -60%
(Aistrike Passive Upgrade)
The cost of every airstrike will drop by 60%.