What you have to do for the last one is this.
Wait till you have 500, don't spawn any units.
When you have 500 buy a salvage,
and then the zombies will be at your base.
wait till you have 200 points and then spawn 5 (by the time your spawning 4 youll have another 50) that will push back the attacking zombies.
keep doing this, (add a house every 2 salvage yards (I beat it with only 1 house)
Waiting till 500 spawning a Salvage, then spawning 5 basic units when the zombies hit you.
When you get enough yehaw wait till their super close and spawn the 1st yehaw. Build a barn
then a explosive house. Then just spawn Farmers and Distillers, and use yehaww and you will win. Thumbs up so people know
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 "Zombie Trailer Park"){kind=icon}
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 "Caravaneer"){kind=icon}
 "Music Catch"){kind=icon}