Thanks for the kind words! I'm glad you enjoyed the experience :-)
The black hole (and sky) shader were both the work of Celyk. He's part of a group of VFX artists that volunteered to take requests during the Godot Wild Jam. It turned out so well, I was determined to make it the visual set piece. Here's the shader in the repo: https://github.com/Maaack/GWJ69/blob/main/assets/shaders/black_hole.gdshader