text: const OPPONENT_HEIGHT = 5,
      OPPONENT_PICTURE = "assets/malo.png",
      OPPONENT_PICTURE_DEAD = "assets/malo_muerto.png",
      FINAL_BOSS_PICTURE = "assets/jefe.png",
      FINAL_BOSS_PICTURE_DEAD = "assets/jefe_muerto.png",
      FINAL_BOSS_SPEED = 10,
      OPPONENT_SPEED = 5,
      OPPONENT_WIDTH = 5,
      GAME_OVER_PICTURE = "assets/game_over.png",
      GAME_WIN_PICTURE = "assets/you_win.png",
      KEY_LEFT = "LEFT",
      KEY_RIGHT = "RIGHT",
      KEY_SHOOT = "SHOOT",
      MIN_TOUCHMOVE = 20,
      PLAYER_HEIGHT = 5,
      PLAYER_PICTURE = "assets/bueno.png",
      PLAYER_PICTURE_DEAD = "assets/bueno_muerto.png",
      PLAYER_SPEED = 20,
      PLAYER_WIDTH = 5,
      SHOT_HEIGHT = 1.5,
      SHOT_SPEED = 20,
      SHOT_PICTURE_PLAYER = "assets/shot1.png",
      SHOT_PICTURE_OPPONENT = "assets/shot2.png",
      SHOT_WIDTH = 1.5,
      PLAYER_LIVES = 3;
  
  function getRandomNumber (range) {
      return Math.floor(Math.random() * range);
  }
  
  function collision (div1, div2) {
      const a = div1.getBoundingClientRect(),
          b = div2.getBoundingClientRect();
      return !(a.bottom < b.top || a.top > b.bottom || a.right < b.left || a.left > b.right);
  
  }
  var game;
  document.addEventListener("DOMContentLoaded", () => {
          game = new Game();
          game.start();
      }
  );