How many levels do you have to complete to get the 19 Enemies discovered achievement? I already defeated Clive and have played at least 15 rounds after that. So what am I missing?
Almost made it, except for a major glitch. It was the 19th night, and after all the Zombies had been killed and the sun had come up it didn't continue to the next screen. So mad!
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 "The Last Stand"){kind=icon}