If you managed to get your hands on the new Nintendo NES Classic today, consider yourself lucky. Like a scene out of the mid-1980s, the miniature game system—which comes pre-loaded with 30 classic video games—is flying off store shelves before it even touches them. While we can’t promise you’ll find one in your stocking this holiday season, we can share these fun facts about your favorite NES games.

1. THE KONAMI CODE’S ORIGINS ARE IN GRADIUS.

Way back in 1985, Kazuhisa Hashimoto was working on the arcade game Gradius. Because he didn’t want to actually play the whole game during the testing process, he developed a little shortcut that gave him a full set of power-ups, letting him live long enough to easily get to where he needed to without dying. When the game went live in 1986, the code was still there. To get full power-ups, all a player had to do was enter the code up, up, down, down, left, right, left, right, B, A.

The trick caught on, and soon, the so-called “Konami Code” could be found in a number of arcade and video games. Most notably, it gave you 30 extra lives in Contra. This super-secret (…or not) code has a special place in the hearts of geeks who have since grown up and used the insider code in websites, in movies, and on TV shows.

2. SUPER C USED A DIFFERENT CODE.

The original Contra was famous for featuring the Konami Code (Up, Up, Down, Down, Left, Right, Left, Right, B, A, Start) to score a player 30 lives. For whatever reason, Super C, the Contra sequel, instead used the code Right, Left, Down, Up, A, B, Start, which only gave a player 10 lives.

3. BALLOON FIGHT WAS ONE OF SATORU IWATA’S FIRST PROJECTS.

Balloon Fight was one of the first games the late Satoru Iwata worked on as he began his career at Nintendo. He later went on to become Nintendo's president and CEO, presiding over the launches of the Nintendo DS and Wii.

4. BUBBLE BOBBLE IS GOOD FOR YOUR BRAIN.

Bubble Bobble may seem rudimentary by today’s video game standards, but it proved that video games can be good for the brain. Educators praised the game’s ability to help kids overcome developmental challenges with its focus on problem-solving, strategy, and motor skills.

5. PIZZA INSPIRED PAC-MAN.

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It’s not easy to create a game based solely on the concept of eating. But Namco employee Toru Iwatani did just that in 1980 by taking the idea of a pizza with a slice missing, and then having it eat a bunch of dots while being chased by ghosts in a maze. (Iwatani has also said that the shape is a rounded version of the square Japanese character for “mouth.") The name of the game, Pakkuman, was inspired by the Japanese onomatopoeia, “paku-paku," which describes the sound of eating, similar to the English word “chomp." As the game was brought to market, the title morphed into Puck Man.

But when Puck Man made his way to North America there was concern that the arcade cabinets would be vandalized by making the P into an F to spell something entirely different. A compromise was reached and the game became known as Pac-Man instead. Thanks to the American marketing machine, the name Pac-Man was eventually adopted for the game all over the world.

6. AN ORIGINAL COPY OF CASTLEVANIA IS WORTH SOME SERIOUS CASH.

The Dracula-based video game Castlevania is particularly valuable these days. Sealed versions of the game sell for upwards of $900, depending on the condition. Original Nintendo NES editions of Castlevania and Castlevania 2 have sold for more than $950.

7. ICE CLIMBER GAVE BIRTH TO SUPER MARIO BROS.

Ice Climber was the first game that Kazuaki Morita worked on. He would go on to refine the game's formula for his next title at Nintendo: Super Mario Bros., where the action moved horizontally instead of vertically.

8. THE REAL MARIO WAS A LANDLORD, NOT A PLUMBER.

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During the development of Donkey Kong, Jr., a Nintendo employee reportedly pointed out that the character looked a lot like Mario Segale, the Italian landlord of Nintendo’s U.S. office. Thus, Mario was born. The original “Lady” character became “Pauline” at the same time in honor of one team member’s wife, Polly.

9. THE GAME VERSION OF MARIO WAS ORIGINALLY A CARPENTER.

In Mario's first appearance in Donkey Kong, he was portrayed as a carpenter. But after a colleague remarked that his overalls made him look more like a plumber, legendary designer Shigeru Miyamoto changed the character's occupation. This alteration also led to the game being set underground in the pipe-populated sewers of New York City.

10. THE NEW YORK TIMES THOUGHT MARIO AND LUIGI WERE JANITORS.

When longtime Nintendo president Hiroshi Yamauchi passed away in 2013, The New York Times ran an obituary that quoted one of its own articles from 1988, in which Mario and Luigi were incorrectly described as janitors. On September 27, 2013—25 years after the article in question ran—the paper ran a correction:

“An obituary on Sept. 20 about Hiroshi Yamauchi, the longtime president of Nintendo, included a quotation from a 1988 New York Times article that inaccurately described the Nintendo video game Super Mario Bros. 2. The brothers Mario and Luigi, who appear in this and other Nintendo games, are plumbers, not janitors.”

11. THERE’S AN EXCITEBIKE ARENA IN MARIO KART 8.

In 2014's Mario Kart 8 for the Wii U, an Excitebike arena became available as downloadable content (DLC), allowing the original game's 8-bit track to be played in a 3D environment.

12. FINAL FANTASY GOT ITS NAME FROM ITS CREATOR’S DESIRE TO RETIRE.

One of the most popular role-playing game franchises of all time got its name from almost becoming the last project its creator ever worked on. According to Hironobu Sakaguchi, he named the game he'd been working on Final Fantasy because he planned to quit the video-game industry if it didn't sell well. Despite the small staff of developers he was afforded for the game, it managed to sell—to the tune of 400,000 copies initially and a long list of sequels, spin-offs, and remastered releases in the years to come. Sakaguchi went on to serve for several years as President of Square USA, the company that first took a chance on Final Fantasy.

13. A U.S. COURT RULED THAT DONKEY KONG AND KING KONG ARE TWO DIFFERENT APES.

Filed in 1982, argued in a federal court in May of 1984, and concluded that October, Universal City Studios, Inc. v. Nintendo Co., Ltd. represented Universal’s demand for a piece of Nintendo’s Donkey Kong action. The game had pulled in $180 million in sales from around 60,000 arcade machines by 1982, and the studio alleged copyright infringement due to the titular villain’s resemblance to King Kong.

Attorney John Kirby, Jr., who represented Nintendo (and for whom it's believed the company’s puffiest character was named, in thanks), pointed out that Universal itself had proved in the case of Universal City Studios, Inc. v. RKO General, Inc. that the plot and characters of King Kong were in the public domain. In the Nintendo case, the court ruled that Universal had acted in bad faith with the suit, had no right to the characters, and that, in any case, the studio had failed to prove that “there was any likelihood that an appreciable number of prudent purchasers [were] likely to be misled or confused as to the source of Donkey Kong” based on the ape’s and the game’s attributes.

14. YES, METROID AND KID ICARUS ARE RELATED.

If you think Metroid and Kid Icarus are similar, there's a reason for that: They were both developed by the same team, including director Satoru Okada, co-director/artist Yoshio Sakamoto, and composer Hip Tanaka.

15. METROID LOOKED TO ALIEN FOR INSPIRATION.

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A fantastic game on its own, 1986's Metroid became the stuff of legends when it saved its biggest surprise for the final moments. After a player completed the game, a short scene revealed that the space-suited, missile-blasting hero was in fact (*gasp*) a woman! This shocking revelation wasn't something that had been planned from the start, and was instead the result of a programmer asking, “Hey, wouldn't that be kind of cool if it turned out that this person inside the suit was a woman?” midway through the game's development. The Metroid team already counted Ridley Scott's female-led, sci-fi horror movie Alien as one of the game's chief inspirations, so they decided to run with that innocent suggestion—and the rest is gaming history.

16. WE MAY NEVER KNOW WHO JUSTIN BAILEY WAS.

Justin Bailey was a programmer. Justin Bailey was an inside joke. Justin Bailey was referencing British slang for "bathing suit."

If you played Metroid in the 1980s, chances are you’ve heard one of these explanations for the game’s most infamous password. Entering "Justin Bailey" and keying in an additional 12 blank spaces allowed players to begin the game with heroine Samus Aran appearing in a leotard instead of her armor while being supplied with a full arsenal of missiles. Where did he come from? Was he man or myth? Or was it all just one very weird fluke?

Turns out, he could very well have just been a bored player who accidentally became the most famous (and hypothetical) NES gamer of all time. (Click here for a much more detailed explanation.)

17. THE ARCADE VERSION ENDING OF DOUBLE DRAGON II: THE REVENGE IS DIFFERENT FROM NINTENDO’S.

The end of Double Dragon II: The Revenge differs on both the NES and arcade. On the NES, damsel-in-distress Marian is brought back to life after being killed early in the story; the arcade version ends on a much more dour note, leaving her dead. You can compare both versions below:

18. A SEQUEL TO MEGA MAN 2 WAS ANNOUNCED, BUT NEVER MATERIALIZED.

In 2010, Capcom announced that it would release Mega Man Universe for the PlayStation Network and Xbox Live Arcade the following year. The company promised that the new video game would have similar gameplay to Mega Man 2 and would give the player the ability to customize their own levels and stages. But a few months later, Capcom canceled the game and apologized to Mega Man fans who were anticipating the new release.

Capcom didn’t disclose a specific reason why they canceled Mega Man Universe, instead citing “various circumstances,” which might have included the exit of the designer of Mega Man Universe, Keiji Inafune.

If Mega Man Universe had actually been released, it would have been the first time the character would have been called “Mega Man” in his native Japan. Historically, the character was called “Rock Man," but was changed when the video game was imported to the United States.

19. NINJA GAIDEN REVOLUTIONIZED THE CONCEPT OF CUTSCENES.

Ninja Gaiden's director, Hideo Yoshizawa (credited as Sakurazaki), wanted the NES version of the game to have a much deeper story than the arcade version, so he implemented 20 minutes of cinematic cutscenes. Though standard now, a story told through cutscenes was revolutionary at the time.

20. BEFORE PUNCH-OUT!’S OFFICIAL RELEASE, 10,000 JAPANESE FANS GOT A GOLD VERSION.

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Nintendoficionados who submitted high scores from 1987’s Golf U.S. Course Famicom Tournament received gold-colored Famicom (the Japanese equivalent of the NES) cartridges containing Punch-Out!’s near-identical precursor, with Super Macho Man as its final foe.

21. TO ADVANCE IN STARTROPICS, YOU NEEDED TO HAVE THE BOX.

In StarTropics, to advance the story, players were required to input a code that was attached to a letter. However, the letter didn’t exist in the game; it was physically included in the box the game came in. This obviously caused problems as players could easily lose it (or wind up with a rental copy lacking the letter at all) and be stuck forever, so Nintendo had to reprint the code in Nintendo Power magazine to try and help confused gamers.

22. THE LEGEND OF ZELDA’S “ZELDA” IS NAMED AFTER ZELDA FITZGERALD.

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Despite being conceived in Japan, The Legend of Zelda’s titular princess was named after a native Alabaman. Shigeru Miyamoto confirmed that Zelda Fitzgerald—novelist, feminist, and wife of F. Scott Fitzgerald—was the inspiration for his Hyrulian heroine’s handle.

23. THERE IS SIGNIFICANCE TO LINK’S NAME, TOO.

Originally, The Legend of Zelda was meant to be a game that spanned in-universe time periods, beginning in the canonical “past” and ending up in the “future,” with the Triforce acting as a mode of transport between them. The series hero’s unusual moniker was meant to symbolize his role as a link between the eras. But Nintendo’s current position is that he is a “link” between the player and the game.

24. SHIGERU MIYAMOTO WAS DISAPPOINTED BY ZELDA II.

When gaming site Kotaku asked Miyamoto if he’s ever made a bad game, the designer responded that Zelda II: The Adventure of Link didn’t live up to his expectations. “We could have done more with [Link],” he said. “It would have been nice to have had bigger enemies in the game, but the [NES] hardware wasn't capable of doing that.”

25. GHOSTS 'N GOBLINS IS CONSIDERED ONE OF THE TOUGHEST VIDEO GAMES OF ALL TIME.

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Not only is Ghosts 'n Goblins known as one of the hardest games of all time, you actually have to beat it twice to actually complete it (it turns out the first play-through is all just a dream for the player).