Xevious takes place on Earth. An invading alien race has set up shop, and it's up to the player to send 'em home. The game has a large number of different ground and air-based targets of either belligerent or non-belliegerent nature. In addition to the jumper-based difficulty levels, the game also adapts its difficulty to the player. If the player is successful against a type of attacker, an even deadlier type of attacker shows up to challenge the player.