самая успешная/удобная тактика - не использовать "стрелку вверх"

var towerCost = Array();
towerCost[1] = [50, 100, 150, 200, 300];
towerCost[2] = [100, 100, 300, 700, 1200];
towerCost[3] = [500, 400, 600, 900, 2000];
towerCost[4] = [600, 400, 600, 1000, 1000];
towerCost[5] = [1000, 600, 700, 900, 1200];
towerCost[6] = [2000, 1000, 2000, 2000, 2000];
var missileDamage = Array();
missileDamage[1] = [10, 20, 50, 100, 150];
missileDamage[2] = [40, 80, 220, 500, 900];
missileDamage[3] = [80, 180, 360, 640, 1100];
missileDamage[4] = [100, 230, 460, 820, 1200];
missileDamage[5] = [100, 160, 250, 400, 700];
missileDamage[6] = [100, 200, 400, 600, 800];
var towerDistance = Array();
towerDistance[1] = [220, 230, 240, 250, 260];
towerDistance[2] = [230, 240, 260, 280, 300];
towerDistance[3] = [100, 110, 120, 130, 150];
towerDistance[4] = [270, 280, 290, 330, 350];
towerDistance[5] = [200, 220, 240, 260, 280];
towerDistance[6] = [300, 310, 320, 330, 340];
var towerDelay = Array();
towerDelay[1] = [24, 23, 22, 21, 20];
towerDelay[2] = [30, 28, 26, 23, 20];
towerDelay[3] = [25, 24, 22, 21, 20];
towerDelay[4] = [20, 18, 15, 12, 10];
towerDelay[5] = [50, 50, 45, 40, 35];
towerDelay[6] = [4, 4, 4, 4, 4];