generar un juego que se trate de matar alienigenas con un arma cuya tecla de disparar en lama sea enter y la de movernos w, a, s, d

const startGame = () => {
  //variables
  let player = 0;
  let aliens = [0];
  let bullets = [0];
  let score = 0;
  let shot = false;
  let gameOver = false;
  let speed = 1;
  let gameWidth = 640;
  let gameHeight = 360;
  let gameOverText = null;
  let scoreText = null;
  let winText = null;
  let levelText = null;
  let count = 0;
  let numOfAliens = 5;
  //functions
  const setup = () => {
    gameOverText = document.getElementById('game-over');
    gameOverText.style.display = "none";
    winText = document.getElementById('you-win');
    winText.style.display = "none";
    scoreText = document.getElementById('score');
    levelText = document.getElementById('level');
    player = document.getElementById('player');
    for(let i = 0; i < num