The player begins the game "2 WARPS TO NEPTUNE". After completing each level, the player is one warp closer to a planet. Each time a planet is reached, the player's ship is seen flying towards it and then a short bonus round is played, where the player can shoot enemy ships for bonus points without worrying about being destroyed by them. Each enemy destroyed in the bonus stage scores 100 or 10,000 for all 40. After reaching Neptune, the player is then three warps from Uranus, and progresses through Saturn, Jupiter, Mars, and finally Earth, taking three warps to reach each planet, then repeats thereafter. Stage one and every 10th stage thereafter the enemies do not fire on the player when entering the screen.