ScoreManager.cs

public struct ScoreData
    {
        public string name;
        public int score;
        public float mutliplyer;

        public ScoreData(string name, int score, float mutliplyer)
        {
            this.name = name;
            this.score = score;
            this.mutliplyer = mutliplyer;
        }
    }

    // Defines how much score is added per frame to the display
    public int updateRate = 2;
    public GameObject scoreInfoPrefab;

    private int score;
    private int scoreToAdd;
    private List<ScoreData> scores;
    private List<GameObject> scoreDisplay;

    /**
    * MonoBehaviour Methods
    **/

	void Start ()
    {
        scores = new List<ScoreData>();
        scoreDisplay = new List<GameObject>();
	}
	
	void Update ()
    {
	    if (scoreToAdd <= 0) return;
        scoreToAdd -= updateRate;
	    score += updateRate;

	    // Update text display for the scoreData
        gameObject.GetComponent<Text>().text = score.ToString().PadLeft(8, '0');
	}

    void OnDestroy()
    {
        // TODO For now, submit high score on scene change (which is when this is destroyed)
        SubmitScore();
    }

    /**
    * Publically accessible methods
    **/

    public void AddScore(ScoreData scoreData)
    {
        // Check if player has not taken damage and if so, set multiplyer to 2x
        PlayerPlane player = GameObject.FindWithTag("Player").GetComponent<PlayerPlane>();
        if (player.maxPlayerHealth == player.playerHealth)
        {
            scoreData.mutliplyer = 2;
        }

        // Store score data and add score to score counter
        scores.Add(scoreData);
        scoreToAdd += (int)(scoreData.score * scoreData.mutliplyer);

        // Add text on screen for score
        CreateScoreText(scoreData);

        Debug.Log("Add score:" + scoreData);
    }

    public void RemoveScoreInfo(GameObject gameObject)
    {
        scoreDisplay.Remove(gameObject);
    }

    /// <summary>
    /// Creates a GameObject on the In-Game Canvas that provides current score information
    /// </summary>
    /// <param name="scoreData">The ScoreData to parse and display</param>
    /// <returns></returns>
    private GameObject CreateScoreText(ScoreData scoreData)
    {
        GameObject scoreInfo = Instantiate(scoreInfoPrefab);
        RectTransform rectTransform = scoreInfo.GetComponent<RectTransform>();
        // Set the canvas as parent
        rectTransform.SetParent(GameObject.Find("In-Game Canvas").GetComponent<RectTransform>(), false);
        // Format text into columns and styles
        scoreInfo.GetComponent<Text>().text = string.Format("{0, -15} {1,6:##.##x} {2,-7:#####}", scoreData.name, scoreData.mutliplyer, scoreData.score);

        // Offset below other scores being displayed if needs be
        if (scoreDisplay.Count > 0)
        {
            rectTransform.anchoredPosition = new Vector2(rectTransform.anchoredPosition.x, scoreDisplay[scoreDisplay.Count-1].GetComponent<RectTransform>().anchoredPosition.y-17);
        }
        
        scoreDisplay.Add(scoreInfo);
        return gameObject;
    }

    /// <summary>
    /// Adds the current score to the local highscore data string
    /// </summary>
    private void SubmitScore()
    {
        // Make sure all the score is added to the main variable
        score += scoreToAdd;
        scoreToAdd = 0;

        // Due to the limitations of PlayerPrefs not supporting lists, we'll conjoin everything into a semi colon seperated string
        // In the future, a custom serialiser could be written which can store more data in a nicer fashion
        // Scores are seperate by semi colons, score data is seperated by colons.
        // scoreValue:date:username;
        String scores = PlayerPrefs.GetString("HighScores", "");
        scores += String.Format("{0}:{1}:{2};", score, DateTime.UtcNow.ToFileTimeUtc(), "AAA");
        PlayerPrefs.SetString("HighScores", scores);

        PlayerPrefs.Save();
    }