Prepare your defense against the oncoming waves of creeps. Don't let them complete the path. Do that by building your base that consists of defense towers along the way.
Instead of building towers and defending against hordes of monsters, play the opposite as an evil mage that builds his army from the ground up to dominate the lands.
As a united military forces of the whole planet, hold the line at all the directions from the green meadows of Europe and snowy Siberia to the burned cities. Use all the resources to protect your world from aliens.
