Alivader is a 1-player arcade game for the Apple II. You're part of the Earth Protection Force. In the year 2001, mother earth is invaded by alien forces. The player's mission is to destroy as many alien ships as possible in 999 time units. The player controls a small ship which moves horizontally on the bottom of the screen and fires vertically upwards. Alien bombers are worth 50 points. They drop bombs which prevent the player from moving horizontally past that point. The upper alien ships which scroll continuously from the left are worth 20 points for each ship destroyed. Developed by T. Aki and released into the public domain by Baked Apple Users Group in 1980.