Tai

The tiny planet Tai is the last outpost between the advancing Imperial invaders and the planets of the Dorfain System and your mission is to defend the planet until the Republican Battle Fleet arrive to destroy the invaders. The Imperial invaders have targeted the planets core by sending ghostguards and fireballs to destroy it, so in your ship viewed from above scrolling vertically constantly, you must move left and right shooting anything that doesn't belong. If you touch a ghostguard, fireball or the walls then you lose one of nine lives, but if you shoot enough of the enemy then you move through the exit. You now join your Mothership in orbit around the planet and you must move about in various directions shooting any enemy ships. Hitting an enemy ship gains you fuel but getting hit reduces your fuel and when it runs out it is game over.