start : auras, beam, groot, then place maximum den's.
wave 1: play upgrader and/or warden to finish build.
wave 2+: TB monk + upgrader + 2 summoners (dmg and speed), finish upgrade the towers.
how it works: groot (golem) is bigger target than core, ogres will rush for him. Make sure the towers can see the north path so they can shoot from far. Den's are best single targets: ogres will melt before hitting defenses.