NU: Hangman Partway Wrong

.java

public class Hangman {
    
    private String wordToGuess = "t";
    private boolean gameRunning = true;	
    private int guessCount = 4;
    
    public void playGame() {
    
        while (gameRunning) {
            
            // Fake player guess
            String guess = "z";
            
            if (wordToGuess.indexOf(guess) != -1) {
                wordToGuess = wordToGuess.replace(guess, "");
                
                if (wordToGuess.length() == 0) {   
                    System.out.println("You Won");
                    break;
                }
                
            } else {
              guessCount--;
              if (guessCount == 0) {
                System.out.println("You Lost :(");
                break;
              }
            
            }
        }
        
    }		
}