Alien Attack Force

Alien Attack Force is a Space Invaders clone for the TRS-80. There are 9 levels of difficulty. The player gets multiple "bases" (one at a time) with which they can move along the bottom of the screen and shoot the invaders. The player also has several barriers that serve as a temporary defense from the alien bullets (although the player can shoot through them as well). However, the aliens descend very quickly and when one of them touches the ground, the game is over, no matter how many "bases" the player has left.