A strange little side quest
The rules may be simple on screen, but the backstory around Zone Defender is anything but tiny. Games resembling checkers were being played thousands of years ago; evidence of related games reaches back to around 1600 BC. It also connects to a different milestone: Space Invaders arrived in 1978 and helped turn electronic games from an arcade curiosity into mainstream entertainment. The screen is modern; the urge to test skill, pattern and timing definitely is not.