Access class from all scripts

Questions & Answers
1

Is there a way I can call this code from all my scripts:

public class Game : MonoBehaviour {
	private static Game _instance;

	public static Game instance {
		get {
			if (_instance == null)
				_instance = GameObject.FindObjectOfType<Game> ();
			return _instance;
		}
	}

	public void Test() {
		Debug.Log("Test");
	}
}

like this:

Game.Test();

instead of having to do this:

Game.instance.Test() 
//Or
Game g = Object.FindObjectOfType<Game>();
if(g != null)
        g.Play();
2

Yes there is. Make it static, and have the static version call a method on the instance

 public static void Test() {
     instance.TheActualTest()
 }

 void TheActualTest() {
     Debug.Log("Test");
 }

If you do this, you can also let the instance be private, and only access it through public static methods - that usually gives a lot cleaner code.