"CANTURIES" is a mix of the words "centuries" and "can´t", and means that it takes a REAL long time, and that it really can´t do it at all, even with the time.
A good way to win level 23 is to first build a maze that allows for juggling, which shouldn´t be too hard, than spam EVERY wave at once, and then focus on juggling, and, as second priority, upgrade every graound area hitting tower, the dart primarily, and bash and ink. It isn´t unlikely a spawn or two will get by your defenses, but, if you´re good, twenty won´t.
I do care too much about badge bragging, but in this case I guess it fair to do so: Congratulations! You just won the The Man with the Golden Coins Badge and 60 points!
 "Garden TD"){kind=icon}
 "Cube Colossus"){kind=icon}
 "Run Elephant Run"){kind=icon}
 "Toss the Turtle"){kind=icon}
 "Robot Dinosaurs That Shoot Beams When They Roar"){kind=icon}
 "Storm the House 3"){kind=icon}
 "Bunny Charm"){kind=icon}
 "Desktop TD Pro"){kind=icon}
 "Stick Arena: Ballistick"){kind=icon}
 "Windows Escape"){kind=icon}
 "This is the Only Level"){kind=icon}
 "MoneySeize"){kind=icon}