itch.io

Yes. I meant transparency per layer. That way we can have multiple ParallaxLayers in Godot. This would give really nice effects on  scrolling.

I modified your code as an experiment. You can view the results in this video. The video may stutter the first time you play it.

Here's how I got multiple layers:

1. I added another Particles2D node with the same properties and split the particle amount in 80:20 ratio between them. This gave me two Particles2D nodes which together gave the same result as earlier.
2. Instead of capturing screen once, I captured the screen 3 times:
   1. For the 1st capture, I hid both the Particles2D nodes
      
   2. For the 2nd capture, I hid everything except the Particles2D with more stars
   3. For the 3rd capture, I hid everything except the Particles2D with less stars.
3. I removed the background color in the 2nd and 3rd captures in a photo editing tool to add transparency.