Invader

Invader is a 1-player arcade game for the Dragon 32/64.

The player controls a space base at the bottom of the screen that moves laterally, and can fire vertically up. An enemy alien ship moves laterally across the screen, dropping 1 level each trip across. The enemy ship fires towards the player. The player gains 100 points for each alien vessel destroyed. The player starts with 3 lives, and gains a bonus game at 1200 points.