I just checked the source of the OP linked page, and this link is not in the page anywhere.

Likely an unintentional omission!(?)

I'd suggest callouts in <h1>s myself, ideally at the start and the end of the article.

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As an aside, it's... reasonably fast, but not playable. And all the monsters appear to have quietly been turned off, and because the game loop can't see your exact keystrokes you can't cheatcode them back on :P