A strange little side quest
Put Zombie Parade Defense next to the history of strategy games and a few unexpected connections appear. Games resembling checkers were being played thousands of years ago; evidence of related games reaches back to around 1600 BC. And then there is this: Pac-Man went on sale in 1980, and its creator Toru Iwatani famously linked the character's shape to a pizza with a slice missing. That gives Zombie Parade Defense a little more company than it first appears to have.