Shoot whatever moves (or doesn't move for that matter) in 135 planetary systems in 15 empires. Pick up in-game powerups and earn hundreds of upgrade points to unlock better ships with stronger armor, more powerful cooling systems, six-pack missiles, or a terrifying railgun. Uncover all the wisdom that is hidden on every planet, fight off wave after wave of alien aggressors, and adjust your strategy to dozens of attack formations and moving styles.