Hi. Thanks for your help.
Yeah, you are right again. Since the parent layer follows the rocket, the particles are moving at double speed. The problem is that I don’t need the parent layer to follow the rocket permanently: sometimes it may follow other objects or follow no objects at all. This overcomplicates the particle management.
Doubling the number of particles does not prevent the gap between particles.
Actually, it seems that these flaws don’t break the game’s appearance, since the art design should mask them. However, I’d still like to solve these problems, because it is possible to run into them in the future.