To most, it looked like a broken link or a dead end. But to Elias, a digital archaeologist of sorts, it was the Holy Grail. For years, rumors had circulated about a "lost" version of a classic tactical game— Galactic Guardians —that supposedly contained nine experimental levels deleted by the developers for being "too difficult for human logic." He clicked the link. To his surprise, the download started.

The forum post was buried on page forty-two of a site that hadn't been updated since 2009. The title was plain: