The first change to be made is to update the Level class. So, instead of using the current variables for the gravity, bgm, and background, start using a LevelSetting class as a reference.

Let's make a small update in Level.cs file. Add the following lines to it:

[SerializeField]
  private LevelSettings _settings;

  public LevelSettings Settings {
    get { return _settings; }
    set { _settings = value; }
  }

We need to take care of the render of this new property.

We will update the DrawLevelDataGUI method in the LevelInspector class:

private void DrawLevelDataGUI () {
      EditorGUILayout.LabelField ("Data", _titleStyle);
      EditorGUILayout.BeginVertical ("box");
      EditorGUILayout.PropertyField (_serializedTotalTime);
      _myTarget.Settings...