Note to people, this game takes place in 2010, and to be honest I think the swine flu isnt done yet. All of the big pandemics in history have appeared, did a bit of damage (remember, it killed hundreds, if not thousands in Mexico), then dissapeared before resurging, having evolved a little at full strength, so the pandemic hasn't actually started yet.
I would suggest, at least until Insane, to keep your triangles maxed out, as a super triangle will shoot 3 times, setting off anything it hits (up until insane), meaning it has the most widespread and useful damage. For easy I tried to keep the circles at at least 2 points in radius.
 "Pandemic: American Swine"){kind=icon}
 "Polygonal Fury"){kind=icon}