GameData.cs

/*****************************************************************************
 * GameData.cs
 * 
 * Holds pointers to data that may be needed by more than one gameplay
 * state.
 ****************************************************************************/

using UnityEngine;
using System.Collections;

namespace BogeyGreen
{
    public class GameData 
    {

        public GameObject currentLevel;

    }
}

GameManager.cs

/*****************************************************************************
 * GameManager.cs
 * 
 * Stores data that may be needed by multiple parts of the system.
 * 
 * Uses a state machine to control the logic of the game.
 *
 ****************************************************************************/

using UnityEngine;
using System.Collections;

using FiniteStateMachine;

namespace BogeyGreen
{
    public class GameManager : MonoBehaviour 
    {
        /*********************************************************************
         * PRIVATE DATA
         ********************************************************************/

        private StateMachine gameFSM;

        private GameData gameData;

        /*********************************************************************
         * START
         ********************************************************************/

        void Start()
        {
            this.gameData = new GameData ();

            SinglePlayerGameplayState singlePlayerState = 
                new SinglePlayerGameplayState (this.gameData);

            this.gameFSM = new StateMachine (singlePlayerState);
        }

        /*********************************************************************
         * UPDATE
         ********************************************************************/

        void Update()
        {
            this.gameFSM.update ();
        }

    }
}