Someone on the forum complained that the enemies in Paradox Vector were too fast. I took this as an individual preference at the time, I thought they were fast, but not so fast as to be of concern to most players.
However, I recently updated my graphics card and realized that the enemy speed (for the green spider-like robot guards and the green floating eyeball guards) was somehow linked to the framerate!
This was poorly designed and should have been discovered during testing, but I guess I did not have access to a fast enough graphics card at the time.
So I have made the guard movement independent of frame-rate, as it should have been at the first.