There is an end. There is a level that may vary for each map that is impossible to pass. It is because at a certain level the attackers get too strong even if you have the best defense possible. The turret spots would just run out. That stage is the end.
To the extreme walkthrough. Lyne. Made by Benfen. Rocket+laser combo to start (rocket first). Make 3. Build 2 cannon and max damage. When full, move a laser and make a Nuke combo with the 2 cannons and rocket. Max damage+ as many times as possible on nuke. Do more nukes till 1,500. Done!!
 "Amorphous+"){kind=icon}
 "The Last Stand 2"){kind=icon}
 "Dad N' Me"){kind=icon}
 "The Next Floor"){kind=icon}
 "Mud and Blood 2"){kind=icon}
 "Endless Zombie Rampage 2"){kind=icon}
 "Onslaught2"){kind=icon}
 "The Endless Zombie Rampage"){kind=icon}
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