Well, it's 30 years later and I'm still playing the game. I would attribute it all to the action pace of the game. The graphics might be very basic, but I've come to see that as instrumentation or heads up display graphics. Yeh, overall, great game.
Aside from my strange LunarLander fantasies. StarRaiders was one of the first games that entirely lifted me out of this world and plopped me elsewhere.
It was one of the few games I could charge my friends to play. Free if you would act as co-pilot and man the keyboard!