It's the finishing touches which separate the good from the bad. The good ensure initial playability by ham-fisted novices, long use by difficulty levels and enjoyment by attention to detail. A personal tailoring option - selecting three to five lives, bonus life, five difficulty and volume levels - raised hopes which were not disappointed.
The aim of the game is a round-trip mission to neighbouring planets, rescuing spacefloating astronauts. Each planet is defended by hostiles: once these are cleared, all nearby astronauts appear for a brief rescue period, before mutating into deadly aliens. Contact with these or any hostile causes you to explode. Shields will save you but their power is limited.
The ship rotates in eight directions, thrusting forward only and bounces off the screen edge. Rotation controls are very sensitive. needing precise control if you are not to spin helplessly.
The sound and music are well-chosen, the graphics excellent. Display shows score, hi-score, lives, rescues and shields, if you have time to look. End screen gives details of achievement and rating. Exciting and addictive. Get it.