Good work mate, I liked the music at the start, unfortunately it does not loop, but it is very good.
Viewing post in Bunker Buster jam comments
The loop setting is not on the audio stream itself, I also struggled a little with it, you actually need to double click the audio file inside the editor file system, it will open the import window, there will be a check box for looping, check enabled and click reimport. Then when the music finished Godot will automatically play it again.