In Reflex Guardian, your objective is to defend your base by destroying incoming creatures using color-matching weapon controls. As creatures approach, you must press the button on your control panel that matches the closest creatures color to destroy it. Stay alert, react quickly, and strategically use your power-ups. Special creatures, like Mutant Creatures, flash and require three hits to be destroyed, while Mega Creatures need multiple hits. The game ends when creatures reach your base or if you press the wrong color button more than three times.