The Story Behind The Web’s Weirdest, Hardest Riddle

David Münnich, Notpron’s 32-year-old creator, says it’s almost impossible to solve alone–and he had help building it along the way.

The Story Behind The Web’s Weirdest, Hardest Riddle
[Photo: Flickr user Sergey Galyonkin]

In 2004 a small website appeared that contained a browser-based game called Notpron, which has since been hailed as “the hardest riddle on the Internet.” It consists of a series of 140 puzzles and riddles that get progressively more complex. Completing the game requires knowledge in a diverse range of fields including HTML programming, sound and graphics editing, music apprehension, research skills, and even remote viewing.


Out of the 17 million players that have attempted the game in the last decade only 31 have completed it. That’s just one in every 550,000 players–or, to put it another way, the chances you’ll be hit by lightning once in your lifetime are 41 times greater than they are for you solving Notpron.

To celebrate the game’s 10th anniversary I asked David Münnich, Notpron’s creator, to go down the rabbit hole of how and why it was created–and what it all means.

“From a game design standpoint the main idea behind Notpron is that it’s doing one thing totally different from all other games,” Münnich says from his home in Saarbrücken, Germany. “Usually you start a game and the game tells you what to do, and you have to act inside that system. Notpron, however, expects you to work around the system, without even telling you to do so.”


This “working around the system” could easily be the unofficial theme of Notpron. The game begins simply enough on level 1 with a rather creepy image of the front door of a house. To pass level 1 you must get inside the house, which you can do easily enough by clicking on the door. Level 2 then features an image of an interior door, but you’ll never make it past this level if you think think inside the borders of the web page that the game is presented on. Instead, you need to look to the browser’s address bar and manually change the URL to progress to level 3.


“You have to do things that would be considered totally user unfriendly in a normal case,” Münnich says of the game, which on the surface looks like it’s just made up of 140 stills of pictures and text, sometimes accompanied by music or sound effects. If you only concentrate on what you see, read, or hear you’ll never crack the riddle. “You have to change the address in your browser, you have to read the source code of the website, you have to download a picture and edit it so important information becomes visible. You have to understand what the riddle is made of [at its most technical level], which is files in folders, basically. And you need to understand how there are different file formats and what they mean. So if you don’t know anything about how a computer works, you will be totally lost.”

Level 64

But don’t think technical prowess are the only muscles the game asks you to flex. True to the “working around the system” theme, players at one point even need to step away from their computer to advance to the next level.

“Level 72 [is] my favorite level, because we force the player to leave the monitor and actually handcraft something, which is necessary in order to progress,” says Münnich.


If you don’t know anything about how a computer works, you will be totally lost.

It’s this blending of the digital and real worlds that remind me of another mysterious Internet puzzle I’ve written about, Cicada 3301. There are many similarities between the two: riddles that require deep technical knowledge, intensive research, and interacting with the real world. Cicada 3301 debuted eight years after Notpron, though no one knows who’s behind it. I ask Münnich if he’s ever tried solving Cicada.

But Münnich says he’s never heard of it, then adds, “To your surprise, I am not a big riddle solver.”

Münnich is right, I’m shocked the guy who created one of the greatest Internet riddles of all time isn’t a riddle solver. You’d think the creator of Notpron would be sitting around working on crossword puzzles and reading all the Agatha Christie and Symphosius he could. But Münnich is a now 32-year-old game developer who has always been fascinated with traditional gaming.


“I had a passion for making games since I was a little kid,” he says. “Of course I couldn’t really make any for technical reasons, so I was painting Super Mario levels on paper.”

Through his teenage years Münnich progressed from drawing levels to becoming a level designer for German firms. Then in 2004, at the age of 22, Münnich one night had an epiphany after being inspired by another website.

“My inspiration for Notpron was a riddle kind of website that was called ‘This Is Not Porn’,” which doesn’t exist any longer, says Münnich. He decided to quickly make up a few riddles of his own–the first five levels of Notpron. “To make my game I just temporarily called the folder ‘notpron’ that I put in all the stuff. ‘Pron’ was just an Internet way of misspelling ‘porn’ on purpose. So obviously not much thought went into that.”


But almost overnight thousands of people began showing up at Notpron to try the riddles.

“And when there have been tens of thousands of people on the page, it was too late to change it,” Münnich says. “But for this kind of game it’s kinda cool to have a name that makes people wonder what it actually means, so that’s fine.”

Level 54

As traffic grew and potential riddle solvers kept coming, Münnich began adding more levels. After the first five, he added another dozen. Notpron then grew from around 20 riddles to 50, then 70, then over 100, to, finally, 140 levels.


“I started to turn everything I looked at into a riddle,” says Münnich when I ask him how he created so many. “Like I saw a Twix bar in a supermarket, and I remembered that it was called ‘Raider’ in Germany earlier. So there is the foundation for another riddle.”

But Münnich doesn’t claim the credit for all of Notpron’s 140 riddles. As the game grew players would begin to send Münnich their riddle ideas. Most he rejected, but quite a few made it into the game. Münnich credits one player, Christine, in particular.

“She was a Notpron player and contributed one riddle at first,” he says. “And then we got to know each other better and she made like 30 in the end.”


As for what it takes to make a good riddle?

“When you get down to it, most riddles are very simple in their essence. Just finding out what to do makes it appear so complicated. People really overestimate the process of making a riddle. They keep thinking I must be some kind of superbrain. In reality those who solve the riddles are masterminds.”

Yet only 31 have successfully completed all 140 levels–that’s a success rate of only 0.00018%. That low figure is all the more extraordinary considering the whole cottage industry of forums and sites that have sprung up offering advice and how-to’s to beat the game.


“I don’t think anyone beat the game all alone, because you need to possess so many different skills, that it’s nearly impossible for a single person,” Münnich says. “Usually it’s little groups of friends who beat it step by step [with] everyone’s strengths being put to use.”

When I ask him if any of his friends have ever beat the game, Münnich says, “No, they all get frustrated after six levels and leave it. But some of those that beat it became friends.”

Level 56

Münnich doesn’t track stats for the shortest amount of time anyone has ever beat the game in, so he says he can only rely on what people have told him. Three months is the stated record. But given the challenging nature of Notpron, it’s understandable that many will give up along the way.


“In the site stats you can see an exponential curve. Almost all reach level 2, but then it’s going down rapidly. So most leave in level 2, another big bunch in level 3. If someone reaches level 9, he or she is most likely going to stick to it and stay,” he says. “It’s something that people are going on a long journey with, and when they are through they are looking back at it in a very nostalgic way.”

Those that complete the game are given a certificate that reads: “He/she persisted with a broad range of complex ways of thinking, while maintaining focus and dedication over a long period. His/her detective skills have been tested to the limits, yet the smallest hint proved sufficient to solve the most complicated tasks.”

No certificates have been issued in 2014.


Throughout history riddles have been used to test us, to show that we are worthy, to reveal something about the human condition. A modern-day riddle that attracts 17 million sleuths surely must have a deep philosophical message–a grand payoff along the lines of The Riddle of the Sphynx, right?

“You overestimate 10-year-ago-David,” Münnich says. “I just had a quick idea and quickly made up five little riddles [then] I just kept adding riddles as long as I had ideas and fun with it” adding that Notpron was just “designed to be mysterious without any essence.”

“It’s a shame really,” he says. “Nowadays I would have a real background that would be mysteriously revealed step by step with the big twist in the end… or so. I’m sorry to spoil it, but Notpron however is just a series of riddles. If you beat one, you get to the next one.”


But then Münnich reveals there is one caveat to what he’s just told me. In the years since he first created the game–as he slowly added more levels–his interests also expanded to areas outside mainstream technology and science.

Level 35

He created a four-hour documentary on the controversial Five Biological Laws of Nature by the German physician Ryke Geerd Hamer. “[His] discovery shows how any organic and psychological changes in the body happen and it contradicts all mainstream views very very much,” says Münnich. The documentary is currently the second most-watched German documentary on YouTube with over 2.4 million views (it’s subtitled in English for those interested).

Münnich’s increasing interest in the experimental, fringe, and metaphysical prompted him to add a special reward for those that beat level 140 of Notpron. He wouldn’t tell me what it was–only 31 people besides himself knows–but he did reveal it has something to do with remote viewing.

“I made sure the last one is really special, and if you beat it, you experience something that might change your whole idea of how the universe works. Doesn’t that sound mysterious and provoking? But I actually mean it.”

But the reason most people will play Notpron isn’t for some metaphysical awakening, according to Münnich. “Our society makes people try to prove how smart they are, so this attracts them.”

As for Münnich his payoff in making the game seems to be taking joy from the community that has sprung up around it and the friends he has made from it–and even from the sites that have copied Notpron.

“There are over 100 clones; we had an alphabetic list of them on the Notpron forums. It’s cool to see that it inspired so many people,” he says. And after 10 years he’s still amazed at how popular the game is. “That’s pretty cool. You’re proud when a person you met for a different reason goes ‘YOU made that?’”

Still, that doesn’t seem to stop the person who used to draw Super Mario levels as a child from having doubts today.

“On the other hand,” Münnich says. “I think that it’s been done pretty amateurish and I could do it a lot better today.”

What do you think? Start here.


About the author

Michael Grothaus is a novelist, journalist, and former screenwriter. His debut novel EPIPHANY JONES is out now from Orenda Books. You can read more about him at


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