Cheat Mode:
Press Ctrl + Alt + C and enter any of the following codes:

Delian Treasury        Add 1000 Coins 
Ambrosia               Win Scenario 
SoundFrags             Sound Effects
Fireballs from Heaven  Strike a Particular Piece of Ground with Fireball
Bowvine and Arrows     Towers Shoot Cows Instead of Arrows
Cheese Puff            Dairy Workers Put on Cheese Suits

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Hints

Shoot Cows From the Sky:
Enable the Bowvine and Arrows code followed by the Fireballs from Heaven code to shoot cows from the sky.

Thanks to Revolution readers Fabkill and Thunderstorm!