Battle your way through waves of incoming aliens as you try to shoot them down while not crashing. Beware, as you advance through the phases they become more aggressive, and you'll need to be quick to survive. Don't let too many aliens pass or they will destroy the galaxy and it's game over. Make sure to collect extra lives and invincibility along the way- you're sure to need it. Make sure to save your invincibility for when you really need it! They don't come around often, and will protect you in critical moments, giving you a chance you catch your breath and get back into the fight. Good Luck!