QS Asteroids (1981)

QS Asteroids is a fairly basic conversion of the original arcade game. The action starts immediately after loading (no title or options screens here) and players finds themselves in a space ship in the middle of the screen with numerous asteroids passing by. To control the ship, two keys are used for rotating it, one for shooting and another for thrusting it forward. Shooting can be done in eight directions. On an unmodified ZX81, the ship is represented by a number which changes with rotation (For example 0 means it's pointing up, while 4 is down) and the asteroids are o's, while users with a QS CHRS board get graphics more similar to the arcade original. The player starts with three ships and after 10,000 points a bonus ship is given. Asteroids appear in waves. The first one has two large ones and the number increases with each new wave.