One of the coolest components of all these recent 25th anniversaries for big Nintendo franchises has been the onslaught of interesting trivia that's turned up. President Iwata's reflective interviews with developers of the games have been a gold mine of unique nuggets of truth, which we've celebrated through past features likeand

#1:+Armorless+Samus+is+All-American

Not+playable+in+Japan.

#2:+The+Origin+of+Samus'+Morph+Ball

The+result+of+programming+problems.

#3:+Samus+&+Sigourney

Two+different+Ridleys.

Well, as we've already pointed out in a couple of articles already, the next big NES 25th anniversary approaching is Metroid's. We're now only a couple of weeks away from the day the first game in Samus Aran's famous series first went on sale in Japan, and we fully expect a new wave of interesting Metroid trivia to follow from the inevitable Iwata Asks columns that pop up dedicated to remembering the franchise next month.But why wait for those?There are enough interesting little tidbits already rolling around my brain and out there in the depths of the Internet to get a jump on the trivia train this time, so I'm going to get this thing started right here today. Here are six things you didn't know about Samus Aran . And if you do actually already know some of them, keep count of how many of the six you'd already heard about.OK, OK, so everyone everywhere knows about how Samus Aran was originally a dude. The developers switched her gender over to female partway through development of the first Metroid, then only revealed her womanliness in the ending credits if you completed the game fast enough. And then you could even play through the game again with her gender totally unobscured, as an armorless version of Samus wearing only a bikini that was available if you typed in a proper password.But that never happened in Japan. Since Metroid was first released as a Famicom Disk System title in Nintendo's home country, it had save slots to record players' progress and no password system. The passwords only came into the picture with the American localization of the game in 1987, and it was only with the password feature that you could access Armorless Samus. (A.K.A. "Justin Bailey" Samus, named for the most popular password that triggers the costume swap.)So the playable bikini mode was basically just added as a bonus for Americans. It would then go on to be included in Europe's version of the game as well, but poor Japanese players were stuck with just the normal, fully-armored Aran. They had to wait years for the introduction of the character's form-fitting Zero Suit to finally get to control her outside her armor.Samus Aran equips her versatile Chozo Power Suit with all kinds of crazy armaments and upgrades throughout the Metroid games, but none is more iconic than the first power-up she grabs before all the rest -- the Maru Mari, nowadays known as the Morph Ball. It's an ability that lets our hero compress her body down into the size and shape of a simple sphere, which then lets her fit through small spaces as she explores her environments. It's been a part of every Metroid game, even the 3D titles have utilized it, and one entire spin-off (Metroid Prime Pinball) is wholly based on the ball-shaped form.And it only exists because of a lack of programming skill.Nintendo's programmers and graphic designers couldn't quite handle the task of animating Samus getting down on all fours and crawling through tight spots back when the first Metroid was in development. It was too tough for them to figure out, apparently. In fact, Samus can't even crouch in that first game either. Standing straight up and down was the only posture they could manage for her, and running, jumping and firing her weapons all worked at full height. Those crawlspaces though? Not a chance.So they just made her turn into a ball. A perfectly acceptable solution for an 8-bit title and its relative lack of realism -- but if you think about it, it's been pretty ridiculous since then. She's a woman wearing a suit of armor normally, that makes sense. But what happens to her when she morphs? It's like having a human riding inside a Transformer and staying in there when it transforms. That's a recipe for a squished, dead human right there.Maybe Iwata will ask about that.Have you ever put together how similar the Metroid series is to the film Alien film franchise? Nintendo's games might not have existed if not for the influence of the movie brand, as the parallels are numerous.The first is just the overall science-fiction setting, which no Nintendo game had ever explored before. And then there's the fact that Samus is a woman and the lead hero of the series, just as Sigourney Weaver's character, Ellen Ripley, serves in that same role for Alien. And the two characters are out to destroy a lethal alien menace that's threatening humanity.The later Metroid games push the characters' connection even further, as Ellen ends up bonding with the xenomorph species she once sought to annihilate and Samus grows attached to the Metroids as well -- saving the baby Metroid in Metroid II's ending sequence, bonding with it as a major plot point of both Super Metroid and Metroid: Other M, and even having herself injected with Metroid DNA in Metroid Fusion to save her life. (Not unlike Ellen Ripley getting cloned with xenomorph biology.)The most direct homage is in the name of Samus' arch-enemy, though -- the endlessly reborn space dragon Ridley was named after Alien's director, Ridley Scott.We'll see the connection between the Alien and Metroid franchises grow even closer later this year, when Aliens: Infestation launches for the Nintendo DS. It's a side-scrolling adventure from WayForward that is pretty clearly drawing on Nintendo's Metroid designs for inspiration -- in a really good way.