Invasion

Invasion is a 1-player arcade game for the VIC-20.

The player is under attack by alien vessels, which approach one at a time from the left, attempt to grab a power supply from the right of the screen, and then escape. The player must defend themselves by launching missiles from the top and bottom of the screen, one at a time, to try to destroy the alien vessel. The player receives 10 points for each vessel destroyed, and it's game over when all 4 power supplies are lost. The player receives a final rank for their defensive performance.