It appears that the "wormhole" is off center. If you zoom the page, you'll notice that each step brings the tunnel closer to the center of the screen. At zoom

It appears that the "wormhole" is off center. If you zoom the page, you'll notice that each step brings the tunnel closer to the center of the screen. At zoom level 6 (counting from 100% as level zero) you are viewing from inside the tunnel, but only just. At zoom level 8 (maximum), the view is almost at the center of the tunnel. If I had to take a guess, the page fails to calculate the center of the viewport, using (0,0) as its target coordinate; but (0,0) is top-left.