Really well done and simple game. The laser is so fun to use and delete all the asteroids and aliens with in go. It seemed that I could use the laser forever because I gained energy from the enemies I killed after using it. I don't if this intended but it felt a bit like an exploit, but also it was very fun to abuse so great job either way.
I don't know if you know this, but the game doesn't properly scale in full screen, this is pretty simple to fix in Godot. Go to the project settings, then window, and change the stretch mode to viewport, and the aspect to keep. This will make your game will stretch and squash without losing its aspect ratio. I don't know why this isn't default, and its my least favorite part of Godot because not doing this messes up so many games' UI once they've been uploaded.
Anyway... great game!