The forces of darkness have burst into our world; they walk along the land destroying kingdoms one by one. Not long ago we received a report from our scouts that evil forces have reached our borders...

3 difficulty levels, 50 waves of creeps with different speed and immune  abilities, 6 types of towers (freeze, stone, poison, ground,  sharp, fire). Each tower may be upgraded into 4 ways: damage, range, attack rate and features.