html, body {
  margin: 0;
  padding: 0;
  background: black;
  overflow: hidden;
  height: 100%;
  width: 100%;
}

canvas {
  display: block;
  width: 100vw;
  height: 100vh;
  background-color: #222;
}

#gun {
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  height: 320px; /* Looks proper now */
  pointer-events: none;
  image-rendering: pixelated;
  z-index: 10;
}

#enemy {
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  height: 340px; /* Resize for realism */
  pointer-events: none;
  image-rendering: pixelated;
  z-index: 9;
  display: none; /* Controlled via JS */
}