A huge chain of cylinders are heading to Earth to conquer us from an advanced and warlike alien race. Inside each cylinder are cities, fields, factories, power stations and military bases, everything an invading force needs to colonize another planet. Several attempts have been made to destroy this chain but all have failed, until now. You are Earth’s last hope as you fly your craft above the surface of the cylinders in an attempt to stop them, but Droidans patrol the cylinders and will try to destroy you over eight levels. You are armed with a gun, and you can either blast or avoid the waves of Droidans but if you are hit by one then you lose one of five lives.