Great job making 2-in-1 games using Godot for first time! Took some time to get used to the controls. The feeling of putting your own constellations to use was quite pleasing.
Potential idea if you plan to expand the game: different patterns could have different effects when casting them, ex. if you make a more circular-looking, then the spell will have a wider range but travel slow. Or if you make a sharp-looking shape, it travels fast and can go through multiple meteors. I can also see this work well in VR, but that's another can of worms. :P
Overall, pretty original idea and a fun game.