A simple, self-imposed challenge to beat 30 waves in Ratropolis without the use of any military units with the scientist leader. Honestly, overall it wasn't too difficult once you get a start. But getting a start is honestly the biggest problem in itself, since it relies on getting something from your leader ability to defend against the initial few waves.
In this run I got basically the perfect advisor super early, which applies Electrons every time a building is attacked - walls count as buildings. 3 Electrons = Enemy gets stunned and takes a burst of damage.
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