Star Shield 6
Welcome to Star Shield Cadet Orientation. As you may know, a number of star systems are going dark - encircled by alien infestations. Our mission is to vigorously defend the light that warms the colonies. We need you to punch holes in darkness.
We stand between our fragile colony and these hostile invaders. Each Star Facility defends a six-sector patch of space. Please familiarize yourself with these control systems.
A numbered shield-unit is dropped from the facility by tapping an empty sector. Each unit is lovingly built here in the colony at significant cost - use them wisely.
Shield-Units explode when the number of full sectors in a continuous row or column matches the numbered designation on the block. Please note the shield-unit itself is always included when counting full sectors - a common rookie mistake.
Notice the invader's display include various dots. These roughly indicate the remaining mass. Completely cleared invaders usually explode damaging nearby sectors. Advanced Cadets try for chain-reactions.
Our Science Team occasionally tests Special Shield-Units. These are stenciled with non-numerical symbols such as a plus or minus - that add or remove one from a shield unit. Faulty units are stenciled with a question-mark. Activate these by clearing a nearby sector.