Germ Warfare is a shoot 'em up game, loosely based on the arcade hit Space Invaders. In this game, you have to shoot down waves of aliens (different each time). The original instructions for the September 1982 issue of Chromasette mentions that you can switch the colorset by hitting "S" during gameplay, and even lists some POKE's to adjust the game parameters (the instructions for each issue of Chromasette can be found on the Color Computer Archive).
Title: Germ Warfare
Author: ???
Publisher: Chromasette
Released: September 1982
Requires: Color Computer 1,2,3, 16K RAM tape or disk, joystick optional.