– At the front of the second set of usable squares, place one Gun Tower one tile apart (minus the one missing at the bottom due to lack of funds). When you get $5, fill in this spot too.
– With the wave down, pause the game, sell the bottom four towers and use the money to buy a Spark Tower that you should put in front of the sandbags. This will kill the incoming wave and start your combos off.
– With $30, earned very quickly add a second Spark Tower to the next sandbag tile below. As the cash quickly comes in, immediately start replacing the Gun Towers you sold so you’re building up a wall of Gun Towers again.
– Fill in every vertical tile with Gatling Towers and then place a third Spark Tower at the most southern sandbag placement.
– You should be rapidly filling up your combo meter, which is perfect as you’ll need it in a matter of seconds.
– Once the runners break your defences, wait for the farthest one to reach the edge of the screen, pause the game and hit the Airstrike button for a massive numbers and cash boost.
– The trick is now to focus solely on adding and upgrading Spark Towers.
– Space your next few Spark Towers apart, but keep them close to the ones by the sandbags.
– Finally, set up more Spark Towers in a row on the tiles closest to their entrance and once the next batch of runners make it through, hit the Airstrike button now for a guaranteed win. Easy enough three stars!