Astro Blast is an Extended BASIC arcade style game with a couple of small machine language subroutines, one for a fast memory copy (used for a bit of the graphics) and the other for sound effects (in addition to some Extended Basic PLAY command sound effects). The game starts with a large UFO (cleverly hidden after the BASIC program itself but brought in automatically when you LOAD it) materializing in the upper right corner. It flies to the center, unloads a bunch of mines, and then slides behind the structure on the screen. The mines start falling one by one and the player uses the arrow keys to maneuver and try to shoot them down before they hit the bottom of the screen (and the keys have key repeat so you can hold down the left arrow and keep moving left, for example). If they make it to the bottom of the screen, they lie around for a bit of time and then explode. If the player runs into the mine before it explodes, they die (as they also do if they are too near to the mine when it explodes). There are also bonus mines (a different color) that randomly show up that are worth more points. Every once in awhile (at random) there are also attack ships that show up in one of the 3 wide chutes and descend down towards the bottom. Your shot can NOT go past the bottom of the chute, so you can't hit them until the emerge from the bottom. The mines and attack ships shoot down at random.
A decent game for being (mostly) in BASIC, with some really good sound effects that people can "borrow" for their own programs.
Title: Astro Blast
Author: Crew A. Reynolds
Publisher: Chromasette April 1983
Released: April 1983
Requires: Color Computer 1 or 2, 16K RAM (cassette) or 32K RAM (disk)