Написал игру, но она работает неправильно, не могу найти ошибку

Ошибка: при нажатии на ячейки открывается иногда верные, иногда неверные соседние ячейки. А если я попадаю, на пустую ячейку (нет мин рядом), то открываются все ячейки +1 мина, которая находится на границе с цифрами. В итоге: Игра не проходима) Игра: https://javarush.com/projects/apps/348774 Предполагаю, что ошибка в логике где-то здесь:

private void openTile(int x, int y) {
       if (gameField[y][x].isOpen || gameField[y][x].isFlag || isGameStopped) return;

       gameField[y][x].isOpen = true;
       setCellColor(x, y, colorOpenCell);
       countClosedTiles--;

       if (gameField[y][x].isMine) {
           setCellValueEx(x, y, colorBoomCell, MINE);
           gameOver();
       } else if (gameField[y][x].countMineNeighbors == 0) {
           setCellValue(x, y, "");
           for (GameObject neighbors : getNeighbors(gameField[x][y])) {
               if (!neighbors.isOpen) {
                       openTile(neighbors.x, neighbors.y);
               }
           }
       } else setCellNumber(x, y, gameField[y][x].countMineNeighbors);

       if (!gameField[y][x].isMine && gameField[y][x].isOpen){
           score+=5;
           setScore(score);
       }

Код игры:

package com.javarush.games.minesweeper;

import com.javarush.engine.cell.Color;
import com.javarush.engine.cell.Game;

import java.util.ArrayList;
import java.util.List;

public class MinesweeperGame extends Game {
    private static final int SIDE = 9;
    private int countMinesOnField;
    private int countFlags;
    private int countClosedTiles = SIDE*SIDE;
    private int score;

    private boolean isGameStopped;

    private GameObject[][] gameField = new GameObject[SIDE][SIDE];

    private static final String MINE = "\uD83D\uDCA3";
    private static final String FLAG = "\uD83D\uDEA9";

    private static final Color colorBackground = Color.ORANGE;
    private static final Color colorOpenCell = Color.GREEN;
    private static final Color colorFlagCell = Color.YELLOW;
    private static final Color colorBoomCell = Color.RED;
    private static final Color colorBackgroundMessage = Color.WHITE;
    private static final Color colorTextMessage = Color.BLACK;

    @Override
    public void initialize() {
        setScreenSize(SIDE, SIDE);
        createGame();
    }

    @Override
    public void onMouseLeftClick(int x, int y) {
        if (isGameStopped) {
            restart();
            return;
        }
        openTile(x,y);
    }

    @Override
    public void onMouseRightClick(int x, int y) {
        markTile(x,y);
    }

    private void createGame() {
        for (int y = 0; y < SIDE; y++) {
            for (int x = 0; x < SIDE; x++) {
                boolean isMine = getRandomNumber(10) < 1;
                if (isMine) {
                    countMinesOnField++;
                }
                gameField[y][x] = new GameObject(x, y, isMine);
                setCellColor(x, y, colorBackground);
                setCellValue(x, y,"");
            }
        }
        countMineNeighbors();
        countFlags = countMinesOnField;
    }

    private List<GameObject> getNeighbors(GameObject gameObject) {
        List<GameObject> result = new ArrayList<>();
        for (int y = gameObject.y - 1; y <= gameObject.y + 1; y++) {
            for (int x = gameObject.x - 1; x <= gameObject.x + 1; x++) {
                if (y < 0 || y >= SIDE) {
                    continue;
                }
                if (x < 0 || x >= SIDE) {
                    continue;
                }
                if (gameField[y][x] == gameObject) {
                    continue;
                }
                result.add(gameField[y][x]);
            }
        }
        return result;
    }

    private void countMineNeighbors() {
        for (int y = 0; y < SIDE; y++) {
            for (int x = 0; x < SIDE; x++) {
                if (!gameField[y][x].isMine) {
                    for (GameObject neighbor : getNeighbors(gameField[y][x])) {
                        if (neighbor.isMine) {
                            gameField[y][x].countMineNeighbors++;
                        }
                    }
                }
            }
        }
    }

    private void openTile(int x, int y) {
        if (gameField[y][x].isOpen || gameField[y][x].isFlag || isGameStopped) return;

        gameField[y][x].isOpen = true;
        setCellColor(x, y, colorOpenCell);
        countClosedTiles--;

        if (gameField[y][x].isMine) {
            setCellValueEx(x, y, colorBoomCell, MINE);
            gameOver();
        } else if (gameField[y][x].countMineNeighbors == 0) {
            setCellValue(x, y, "");
            for (GameObject neighbors : getNeighbors(gameField[x][y])) {
                if (!neighbors.isOpen) {
                        openTile(neighbors.x, neighbors.y);
                }
            }
        } else setCellNumber(x, y, gameField[y][x].countMineNeighbors);

        if (!gameField[y][x].isMine && gameField[y][x].isOpen){
            score+=5;
            setScore(score);
        }

        if (!gameField[y][x].isMine && countClosedTiles == countMinesOnField) {
            win();
        }
    }
    private void markTile (int x, int y){
        if (gameField[y][x].isOpen == true || (countFlags == 0 && gameField[y][x].isFlag == false || isGameStopped == true) ) return;

        if (gameField[y][x].isFlag) {
            countFlags++;
            gameField[y][x].isFlag = false;
            setCellValue(x, y, "");
            setCellColor(x, y, colorBackground);
        } else {
            countFlags--;
            gameField[y][x].isFlag = true;
            setCellValue(x, y, FLAG);
            setCellColor(x, y, colorFlagCell);
        }

        }
    private void gameOver(){
        isGameStopped = true;
        showMessageDialog(colorBackgroundMessage, "YOU LOSER", colorTextMessage, 40);
    }

    private void win(){
        isGameStopped = true;
        showMessageDialog(colorBackgroundMessage, "YOU WINNER", colorTextMessage, 40);
    }

    private void restart(){
        isGameStopped = false;
        countClosedTiles = SIDE*SIDE;
        score = 0;
        countMinesOnField = 0;
        setScore(score);
        createGame();

    }
}