Following Angega Studio's Tutorial with some changes to make it work in Godot 3.x.
Full credit goes to Edward Angeles from Angega Studios for his amazing flappy bird tutorial in Godot 2.1.
- Angega Studios: @AngegaStudios
- Tutorial: Godot Engine Tutorial - Flappy Bird
- Repo: Bitbucket - Godot Engine Tutorial - Flappy Bird
- 3.1 Hints from @esotaridex - repo