Use mouse to place towers.
The orcs and goblins are determined to prepare a campaign against the human race. Prepare your defense against the oncoming waves of creeps. Don't let them complete the path. Do that by building your base that consist of defense towers along the way. Manage and upgrade them to get to higher levels. You have 6 types of towers to chose from once you have enough gold, to use in order to stop 10 different types of creeps attacking in waves. Good luck!