The assault is launched! Enemy spaceships peel out of formation and dive bomb your fortification. If you destroy this squadron of 8 ships, the enemy reverts to a special "night" attack. Your video screen changes to an ominous color. But all is not lost. Destroy the first wave of "night" attackers and your points are doubled! So steady your nerves, keep a sharp look-out and start racking up points— the enemy is upon you!
source: /archive.org/details/program-catalog-for-the-coco-1982/page/n7/mode/2up