#bloque_juego {
  width: 370px;
  height: 550px;
  position: relative;
  overflow: hidden;
  border: 2px solid white;
  background-color: black;
}

.fondo-juego {
  position: absolute;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
}

.nave {
  position: absolute;
  width: 50px;
  height: 50px;
  z-index: 1;
}

.bala {
  position: absolute;
  width: 10px;
  height: 20px;
  z-index: 2;
}

.enemigo {
  position: absolute;
  width: 30px;
  height: 30px;
  z-index: 2;
}