DontDestroyのシングルトン

LoadScene.cs

using UnityEngine;
using System.Collections;

public class LoadScene : MonoBehaviour 
{
	public static LoadScene Instance{
		get; private set;
	}
	public int score = 0;

	void Awake()
	{
		if (Instance != null) {
			Destroy(gameObject);
			return;
		}
		Instance = this;
		DontDestroyOnLoad (gameObject);

		score = 30;
	}

	// click callback
	public void OnClick()
	{
		Application.LoadLevel (1);
	}
}

ReadData.cs

using UnityEngine;
using System.Collections;

public class ReadData : MonoBehaviour 
{
	void Start () 
	{
		LoadScene loadScene = LoadScene.Instance;
		Debug.Log (loadScene.score);
	}
}