A strange little side quest
Put Kingdom Rush 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. That is only half the story. Computer Space reached arcades in 1971 and became one of the earliest commercial electronic arcade games, even though its controls proved demanding for many players. It is a good reminder that simple game mechanics can carry a surprising amount of history.