Editor's take: It’s the sort of thing video game enthusiasts and historians lie awake at night and think about – a treasure trove of early prototypes and concepts that have been locked away for decades, never meant to see the light of day. Nintendo can't be pleased, no doubt, but really, what harm can come from the public release of content that is - in some cases - around 30 years old?

Nintendo earlier this year suffered a massive data breach in which more than two terabytes of legacy data was compromised. The haul reportedly included source code for the Nintendo 64, the Game Cube and the Wii in addition to detailed documents regarding individual system components.

Now more than two months later, even more intriguing details have hit the web.

As Video Games Chronicle highlights, early prototypes for Super Mario World 2 (Yoshi’s Island) and Super Mario Kart have surfaced as a result of the original leak. An early (very glitchy) version of Super Mario Kart is said to feature unused tracks, no drifting and a unique title screen while the Yoshi’s Island build has different UI graphics and music from the original Super Mario World.

One can only wonder why it took nearly three months for the unused artwork to surface. More importantly, what other hidden gems are left to be found in the massive leak?