public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
TargetElapsedTime = TimeSpan.FromTicks(333333);
intro = new Introduction();
instruct = new Instructions();
instruct2 = new Instructions2();
gameover = new GameOver();
timex = new TimeExpired(); // instantiate menus
// use the whole screen
graphics.IsFullScreen = true;
game_engine = new GameEngine(timex, gameover);
}