Sparta achievement tactic: buy 3 quackers, upgrade one to maximum, and one to lvl2. Then buy 60 gunners. That's all. You can leave the game and go get a drink, they deal fine with spartans and get you a achievement. (notice the plus-sign to the right, for the good of all of us).
 "Boxhead: 2Play Rooms"){kind=icon}
 "Storm the House 3"){kind=icon}
 "Feudalism II"){kind=icon}
 "Sands of the Coliseum"){kind=icon}
 "The Peacekeeper"){kind=icon}