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The Nintendo 'Gigaleak' revealed tons of secrets hidden in classic games

What you experience when you play a video game is often not all there is to see. Like movies, games have plenty of things left on the cutting room floor, but instead of being shared in DVD extras, the hidden levels and characters in games are often actually on the disc or cartridge, just buried in the code. Earlier this year, breadcrumbs from a trove of data from old Nintendo games started leaking online, giving gamers a peek behind the curtains of some of the company's most storied franchises. On Friday, the motherload arrived. A massive data dump, dubbed 'Gigaleak,' appeared on 4chan and provided unprecedented access to classic Super NES, Game Boy, and N64 titles, revealing secrets about the games that had been hidden for decades.

Here are some of the best artifacts found so far:

Luigi finally confirmed in Super Mario 64

There have been rumors about Luigi's presence in Super Mario 64, the classic Mario adventure title for the Nintendo 64, dating all the way back to the game's release. Gamers were so sure that Mario's beloved brother must be in the game somewhere that in November 1996, IGN offered up a $100 bounty to anyone who could unlock the character. While it took 24 years to reveal him, it turns out Luigi actually has been in Super Mario 64 all this time. One of the biggest and most noteworthy finds of the Gigaleak is the textures for a 3D model of Luigi, suggesting that developers did at one point intend to put him in the game. The prevailing theory seems to be that he would have appeared in a two-player mode, which was ultimately scrapped but some remnants of the game mode remain.

The forgotten rooms of Super Mario 64

On top of finally revealing the existence of Luigi, the leak also showed off some early rooms that were likely used to test the game during its beta stage. The rooms are a bit haunting, as there is nothing occupying them and they lack the bright and bouncy charm that much of the classic title's level design includes. But it gives an early look at how developers tested the game, and the levels were never likely intended to be seen or played.

CAD tool from Star Fox 2's development

Developer tools were not uncommon finds within the leak, but one particular instance speaks to the veracity of the data being dumped online. A CAD (computer-aided design) tool that was used in the process of developing Star Fox 2 for the SNES was included in the leak and appeared to be used in programming the dialogue that would appear in the game.

While the tool is relatively simple, and nowhere near as attention-grabbing as secret characters and abandoned features, it got the attention of Dylan Cuthbert, one of the lead programmers on Star Fox 2. On Twitter, he expressed shock at seeing the tool again for the first time in decades and confirmed that it was authentic. "I haven’t seen this tool I made for StarFox 2 for almost 30 years, I wrote it in early C++ to teach myself the language more than anything else," he wrote. "Where the hell have hackers got all this obscure data from?"

An unknown Star Fox 2 character

On top of the developer tool, a dive into the data leak also revealed a hidden character developed for Star Fox 2 but who never made it into the game. What is most curious about the unnamed character is that she appears to be fully human. That makes her stand out in a game world that is otherwise entirely occupied by characters that are anthropomorphized animals. Even those involved in the development of Star Fox 2 can't seem to place her or her initial role in the game, but she's already amassing a following, complete with fan art.

A mysterious character called "Super Donkey" in Yoshi's Island

Yoshi's Island might not have been designed for Yoshi at all. What appears to be an early build of the game was included in the Gigaleak, and there is no Yoshi to be found. Instead, there is a different lead who appears to be some sort of mix between a Mario-like figure and something like a Rayman-type character. There are no real details about this character, other than his name: Super Donkey.

Character sheets included in the leak show Super Donkey to have a design resembling Mario beneath his goggles and pilot's helmet, which has led some to suggest that Yoshi's Island was originally going to be a new sort of take on the Donkey Kong world, featuring Jumpman as the main character.

On top of a totally different protagonist, the leaks also showed a completely different user interface for Yoshi's Island (though they at least include Yoshi in the game this time), including a different map screen, unused mini-games, and early test levels.

Early versions of Yoshi in Super Mario World

Before he got his own game, Yoshi was a sidekick to Mario, making his first-ever appearance in Super Mario World for the SNES. The lovable dinosaur character always looked friendly, but early designs of Yoshi revealed in the leak are, quite frankly, a bit terrifying. The prototype Yoshi was thinner, and just has kind of a creepy appearance to him. The design also matches some early art that developers who worked on the game have revealed over the years, lending credibility to the leak.

Luigi gets cheeky and Bowser gets legs in Super Mario World

Yoshi wasn't the only one who got some tweaks from his early designs in Super Mario World. The Gigaleak also revealed some unused sprite designs of other characters, too. One included Luigi seemingly giving the middle finger.

Another appears to show a version of Bowser that had legs. While later versions of Bowser of course do have legs, the villain remained in his flying Koopa Clown Car for the entirety of Super Mario World.

Early versions of Pokémon sprites

Much like the Super Mario World sprites, leaks of early Pokémon titles show some beloved pocket monsters were not always the characters that we know today. A collection of early designs and unused character models were included in the leak, showing off a number of Pokémon that got tweaked before the final version of the game was released.

Uncompressed audio files from N64 games

Perhaps one of the more interesting finds across the Gigaleaks are high-quality audio samples from a number of N64 titles, including Star Fox 64, F-Zero X, and Super Mario 64. These voice recordings give listeners an idea of what the game might sound like if released today, on systems that could support full, high-quality audio. Instead, the audio was compressed so it could fit onto the N64 cartridges, which had limited memory available.