FYI at this moment the full finished project you provide no longer run in latest Godot. I am building from sources using lastest commit.
For some reason, "moving_character" is not assigned properly in LudonautAvatar.tscn associated script KeyboardMovingCharacterController. Tried to clean and reassign but cannot select the MovingCharacter2D, weird.
Maybe a Godot bug?
Anyway, thanks for this asset and tutorial!