@Override
	public void update(GameContainer container, StateBasedGame game, int delta)
			throws SlickException {
		
		TowerGame tg = (TowerGame) game;
		Input input = container.getInput();
		
		if (input.isKeyPressed(Input.KEY_NUMPAD1))
			playBeep1();
		if (input.isKeyPressed(Input.KEY_NUMPAD2))
			playBeep2();
		if (input.isKeyPressed(Input.KEY_NUMPAD3))
			playBeep3();
		
		switch(screen){
		case 0:
			if (input.isKeyPressed(Input.KEY_ENTER)){
				screen = 1;
				playBeep3();
				input.clearKeyPressedRecord();
			}
			break;
		case 1: 
			menuControls(input);
			break;
		case 2: 
			startGameControls(tg, input);
			break;
		case 3: 
			optionControls(tg, input);
			break;
		default: 
			break;
		}
		
		// Turn on and off "[Press Enter]"
		if (flashCount < 0){
			flash = !flash;
			flashCount = 750;
		} else {
			flashCount -= delta;
		}
		
	}