const $life = document.querySelector('#life');

const $$cells = document.querySelectorAll('.cell');
(중략)

let life = 3;
let timerId;
let tickId;

$start.addEventListener('click', () => {
  (중략)
  console.log('시작');

  timerId = setInterval(() => {

    (중략)
  }, 100);

  tickId = setInterval(tick, 1000);

});
(중략)
$$cells.forEach(($cell, index) => {
  (중략)
  $cell.querySelector('.bomb').addEventListener('click', (event) => {
    (중략)
    setTimeout(() => {
      holes[index] = 0;
      event.target.classList.remove('boom');
    }, 1000);

    life--;