Step into the boots of an Astronaut who is part of a non-violent expedition of Astronauts, when they suddenly come under attack from an alien robot army. With no weapon, the Astronaut must lead the defense to save themselves and their people by building turrets to defeat waves of enemies and bosses. During the course of each level, the gameplay evolves from a focus on turret placement strategy to all out chaos and mostly running for your life during the later waves. Experience a story mode with differing environments, enemies, and unique boss fights and a challenge mode that offers replay-able sandbox customization for turret usage, enemy combatants, difficulty settings, and achievement hunting.