It took almost 28 years, but Super Mario 64 players have finally opened an "unopenable" door - using a penguin and a sick backflip

A screenshot of Mario in the Super Mario 3D All-Stars release of Super Mario 64 holding a baby penguin next to its mother.
(Image credit: Nintendo)

It's been almost 28 years, but Super Mario 64 players have finally figured out the impossible. A door which was previously thought to be unopenable has been opened, all thanks to an angry penguin and some fancy footwork.

A lone cabin door at the bottom of Cool, Cool Mountain has sat taunting us for decades, with a pesky wall hitbox stopping us from inching our way close enough to break through it. Those who've played the classic 3D platformer will know this as the cabin you emerge from after diving into a chimney at the top of the mountain, and cruising down a slide before receiving the Slip Slidin' Away Star. The door is fully functional, and Mario has always been able to use it from the inside to load the outside area and unlock the Star, but no one has ever been able to figure out how to get back in through it without using hacks.

That is, until now. As highlighted by Tom's Hardware, in a new YouTube video, content creator pannenkoek2012 shares a discovery made by Discord user Alexpalix1, who found that it is possible to break through the door from the outside. You just need to pull off a nifty little move in order to essentially trick the game into thinking you're walking into it, which Mario needs to do in order to open any door.

For context, the door is right next to an adorable mother penguin, whose baby you need to find and give back in order to receive another Star. Picking up the baby after this will make the mother penguin rightfully annoyed, causing her to chase Mario down. Even before now, players have been able to use the mother penguin's hitbox next to the cabin wall to force Mario through it, but this doesn't actually open the door since he's sent into freefall, plummeting into the void to his doom. 

So, what did Alexpalix1 do differently? Well, as pannenkoek2012 explains, it turns out that for a single frame, Mario can walk in mid-air by turning around. Normally, when Mario finishes his turning around action, he's expected to just start walking again. In the platformer's code, this essentially overrides the regular rule that sends the red-hatted plumber into freefall when he's off the ground, so if he finishes turning around while in the air, for a single frame, he walks. 

Using this logic, Alexpalix1 pulls off a sick backflip behind the mother penguin, whose hitbox pushes Mario through the wall hitbox and into the proximity of the door, and by finishing the turning around action at the right time, the door is successfully opened. It seems like such a tiny difference in strategy compared to what players have been trying for years, but lo and behold, it's made all the difference. 

Are there bountiful rewards waiting behind the door for these efforts, though? Simply, no. There's nothing new to see in there at all since it's the same cabin you can emerge from normally, although pulling off this glitch and then exiting the door can unlock the Star without doing the whole slide section. Slightly underwhelmingly though, pannenkoek2012 explains that this is no faster than just speeding through the section normally, so this discovery seemingly won't have any impact on speedruns. Even so, there's no doubt that this is a momentous discovery, and it's exceptionally cool to see finds like this made after all this time.

If you love Mario, be sure to check out our ranking of the 15 best Mario games of all time.

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Catherine Lewis
News Writer

I'm one of GamesRadar+'s news writers, who works alongside the rest of the news team to deliver cool gaming stories that we love. After spending more hours than I can count filling The University of Sheffield's student newspaper with Pokemon and indie game content, and picking up a degree in Journalism Studies, I started my career at GAMINGbible where I worked as a journalist for over a year and a half. I then became TechRadar Gaming's news writer, where I sourced stories and wrote about all sorts of intriguing topics. In my spare time, you're sure to find me on my Nintendo Switch or PS5 playing through story-driven RPGs like Xenoblade Chronicles and Persona 5 Royal, nuzlocking old Pokemon games, or going for a Victory Royale in Fortnite.