Prepare to defend yourself. Purchase defensive structures, recharge your energy and fight off waves of monsters. Kill bosses and upgrade weapons. Complete the final day and close the portals!
WASD = move
Left mouse button = shoot
Right mouse button = iron sight
Mouse wheel or 1-6 = change weapons
Space = jump
Playing serious head free online game support all smartphones or tablets, such as iPhone, iPad, Samsung and other Apple and android system.