I actually did read your post and it read to me as if it put in the background to get around some sort of issue with how you took the screenshot, but had still placed the images and text on top. What you wrote was:

    So it kind of cheated, though it clearly felt angst about
    it. After trying a few ways to get the stars to line up 
    perfectly, it just gave up and copied the screenshot in 
    as the background image, then overlaid the rest of the 
    HTML elements on top.

Which is only "kind of" cheating if only the background was wrong. Everything being invisible and in the wrong spot doesn't seem like merely "kind of" cheating. You didn't come anywhere close to addressing the problem that the original post was about.

The index_tiled.html version correctly positions the original assets, and to me looks as close as you can get to the screenshot while using the original assets (except for the red text).

The version with the screenshot as a background is where it was asked to create an exact match for screenshot that had been scaled/compressed, which isn't really possible any other way. The article acknowledges this one as cheating.

Better I think would've been to retake the screenshot without the scaling/compression, to see if it can create a site that is both an exact match and using the original assets.

If you look at the diff you'll see that all the planets are off too. So the OP mentioned the starfield but that doesn't explain the planets