Having hard times with passing 9/16 Minesweeper

package com.codegym.games.minesweeper;

public class GameObject {

    public int x;
    public int y;
    public boolean isMine;
    public int countMineNeighbors;
    public boolean isOpen =  true;
    public boolean isFlag;

    public GameObject(int x, int y, boolean isMine) {
        this.x = x;
        this.y = y;
        this.isMine = isMine;
    }
}

package com.codegym.games.minesweeper;

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

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

public class MinesweeperGame extends Game {

    private static final int SIDE = 9;
    private GameObject[][] gameField = new GameObject[SIDE][SIDE];
    private int countMinesOnField = 0;
    private int countFlags;
    private static final String MINE = "\uD83D\uDCA3";
    private static final String FLAG = "\uD83D\uDEA9";


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

    }

    @Override
    public void onMouseLeftClick(int x, int y) {
        openTile(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, Color.ORANGE);
            }
        }
        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 (x == gameObject.x && y == gameObject.y) {
                    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++) {
                GameObject thisField = gameField[y][x];
                if (!thisField.isMine) {
                    List<GameObject> neighborsList = getNeighbors(thisField);
                    int numberOfMines = 0;
                    for (GameObject neighbors : neighborsList) {
                        if (neighbors.isMine) {
                            numberOfMines++;
                            thisField.countMineNeighbors = numberOfMines;
                        }
                    }
                }
            }
        }
    }

    private void openTile(int x, int y) {
        gameField[y][x].isOpen = true;
        setCellColor(x, y, Color.GREEN);
        if (!gameField[y][x].isMine && gameField[y][x].countMineNeighbors >= 1) {
            setCellNumber(gameField[y][x].x, gameField[y][x].y, gameField[y][x].countMineNeighbors);
        }

        if (gameField[y][x].isMine) {
            setCellValue(x, y, MINE);

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

                }
            }

        } else {
            setCellNumber(x, y, gameField[y][x].countMineNeighbors);
        }


    }
}