You need the ink towers for the spawn creeps. Still don't know what they do, but they work. I tried quake and typhoon towers and couldn't quite pull off the time, but ink got it easily. Just saying.
This (impossible) will probably be the least awarded badge on Kongregate for quite some time. Count goes up by about 7/day which means it would need almost a year to catch up to Meisiria.
 "Crush The Castle 2 PP"){kind=icon}
 "Shield Defense"){kind=icon}
 "Battalion: Vengeance"){kind=icon}
 "Papa's Taco Mia!"){kind=icon}
 "The Next Floor"){kind=icon}
 "Desktop TD Pro"){kind=icon}
 "Frantic 2"){kind=icon}
 "Papa's Pizzeria"){kind=icon}
 "Ultimate Assassin 3"){kind=icon}
 "The Space Game: Missions"){kind=icon}
 "Penguin Overlords"){kind=icon}
 "Mechanical Commando"){kind=icon}
 "WhiteboardWar: ChopRaider"){kind=icon}
 "Portal Defenders"){kind=icon}