Thank you for playing it. I had to look up both games you mentioned to understand what you meant, but there are definitely similarities to both, I agree. Minestorm for Vectrex seemed a lot like Asteroid for Atari (one of the first video games I ever played).
I do not think you were experiencing a bug, just an oversight on my part. The chance of a pickup spawning was 1 out of 9 with an equal chance either for the special ability pickup or the health pickup (cutting that chance in half gave you a 1 out of 18 chance for a health pickup to spawn).
After playing the game for too long, I had decided it was too easy and had decreased the chance of pickups spawning. I should have played it longer with the new RNG to make sure the increased difficulty still made it fun.
What would you suggest? Maybe double the chance of a pickup and extend the despawn time? Thank you again for playing it and providing feedback.