ScrollingShooter.ScrollingShooterGame.Update C# (CSharp) Method

        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed
                || Keyboard.GetState().IsKeyDown(Keys.Escape))
                this.Exit();

            //Debug input
            #if DEBUG
            if (Keyboard.GetState().IsKeyDown(Keys.OemTilde))
            {
                GameState = GameState.Splash;
                SplashType = SplashScreenType.GameOver;
                loadSplashScreen(new Credits());
            }
            #endif

            if (Keyboard.GetState().IsKeyDown(Keys.Y) && oldKS.IsKeyUp(Keys.Y))
            {
                //CurrentLevel++;
                if (CurrentLevel < Levels.Count)
                {
                    LevelManager.LevelDone = true;
                }
            }

            float elapsedTime = (float)gameTime.ElapsedGameTime.TotalSeconds;

            // Update according to current game state
            switch (GameState)
            {
                case GameState.Initializing:
                    if (!LevelManager.Loading)
                        GameState = GameState.Gameplay;
                    break;

                case GameState.Splash:

                    if (SplashType == SplashScreenType.GameStart )
                    {
                        if (Splash.Done && Keyboard.GetState().IsKeyDown(Keys.Enter))
                        {
                            //the game is starting, load the first cutscene and update to the first line of dialog
                            SplashType = SplashScreenType.Beginning;
                            loadSplashScreen(new Beginning());
                        }
                    }
                    else if (SplashType == SplashScreenType.GameOver) //Should be Gameover or credits
                    {
                        if (Splash.Done && Keyboard.GetState().IsKeyDown(Keys.Enter))
                        {
                            //Game over reload first screen.
                            SplashType = SplashScreenType.GameStart;
                            loadSplashScreen(new GameStart());
                        }
                    }
                    else if (Splash.Done || Keyboard.GetState().IsKeyDown(Keys.S) && oldKS.IsKeyUp(Keys.S))
                    {
                        //Load next level
                        CurrentLevel = Splash.NextLevel;
                        Reset();
                    }
                    //Otherwise update.
                    Splash.Update(elapsedTime);
                    break;

                case GameState.Gameplay:
                    LevelManager.Update(elapsedTime);
                    if (!LevelManager.Ending)
                    {
                        GameObjectManager.Update(elapsedTime);
                        ProcessCollisions();
                    }
                    if (LevelManager.LevelDone)
                    {
                        switch (CurrentLevel)
                        {
                            case 1:
                                SplashType = SplashScreenType.EndLevelOne;
                                Splash = new EndLevelOne();
                                break;
                            case 2:
                                SplashType = SplashScreenType.EndLevelTwo;
                                Splash = new EndLevelTwo();
                                break;
                            case 3:
                                SplashType = SplashScreenType.EndLevelThree;
                                Splash = new EndLevelThree();
                                break;
                            case 4:
                                SplashType = SplashScreenType.EndLevelFour;
                                Splash = new EndLevelFour();
                                break;
                            case 5:
                                SplashType = SplashScreenType.EndLevelFive;
                                Splash = new EndLevelFive();
                                break;
                            case 6:
                                SplashType = SplashScreenType.EndLevelSix;
                                Splash = new EndLevelSix();
                                break;
                            case 7:
                                SplashType = SplashScreenType.EndLevelSeven;
                                Splash = new EndLevelSix();
                                break;
                            case 8:
                                SplashType = SplashScreenType.GameOver;
                                Splash = new Credits();
                                break;
                        }
                        GameState = GameState.Splash;
                        Splash.Update(elapsedTime);
                    }
                    else if (LevelManager.ResetLevel)
                    {
                        //Should be handle by player death method.
                        Reset();
                        LevelManager.ResetLevel = false;
                        Player.Score = 0;
                        Player.Lives = 5;
                        Player.Health = Player.MaxHealth;
                        Player.Dead = false;
                    }
                    break;

                case GameState.Scoring: //Not used
                    GuiManager.Update(elapsedTime);
                    if (GuiManager.tallyState == GuiManager.TallyingState.PressSpaceToContinue
                        && Keyboard.GetState().IsKeyDown(Keys.Space))
                    {
                        GameState = GameState.Splash;
                        Music = Splash.Music;
                        if (Music != null) MediaPlayer.Play(Music);
                    }
                    break;
            }

            oldKS = Keyboard.GetState();
            base.Update(gameTime);
        }