When developer Dave Theurer began to design Tempest, he sought to make a first-person game in the style of Space Invaders. However, after performing a marketing review and playtesting the prototype with his colleagues, they found it to be "okay, but it wasn't a lot of fun". At the same meeting, the team struggled with other concepts and considered cancelling the project, until Theurer suggested a similar idea. As a child, he was not allowed to watch movies at home, but while he was in the fifth grade and away at patrol camp, he ended up seeing an unspecified movie about monsters from the center of the Earth crawling up through a tunnel in the ground and attacking humans. That imagery stuck with him throughout his life as a recurring nightmare, where he struggled to defend against the monsters. The team liked that idea better, and the project was saved. Theurer ended up modelling the first-person Space Invaders setting after his nightmare by wrapping it into a cylinder, having enemies climb up the inside of the cylinder, and having the player shoot at them by orbiting around the top of the cylinder in a circle, forming the basis for Tempest.