– You actually only need two towers to slam-dunk the three stars on Heroic difficulty, the Gatling Gun Tower and the Spark Tower.
– Place a Gun Tower on the first and last most western tiles, and then place the rest two squares apart in-between.
– Once you’ve gone four rows deep, focus your money on upgrading just the first row of Towers up to level three.
– Once you’ve built up over $60, sell the middle two towers on the front row and stick in a Spark Tower. Repeat the selling and swapping with the full front row of Gun Towers.
– When the helicopters fly over, the odds are you won’t take them all out, but you should have an Airstrike ready to call in, so when the one closest to the exit is about to leave, pause the game and call in the Airstrike.
– Use this glut of money to swap out the second row of Gun Towers and upgrade all Spark Towers to level three.
– In mere seconds you’ll sail across the 1,000 required total and you’ll most likely have another Airstrike you can use. Job done.