Alright, so for those lazy enough to download the demo and complete it, here's how to unlock the extra level.
1.Head to your appdata folder
2.Find the Godot Folder in Roaming
3.Head to app_userdata
4.Make a new Folder called "Beat Banger Demo"
5.Make a .txt file and name it beat_banger_data
6.Change the extension to .json
7.Open it and paste this:
JSON:
{
"levelsUnlocked": 0,
"played_demo": true
}
8.Make sure it's in JSON formatting
9.Done
I reckon this is all that is needed. Otherwise let me know.