Originally written and published for StropsE.com, written December 19th, 2020

Are you a fan of hidden messages and secret codes? Of seeing the writing on the wall, hidden from all but the most discerning eyes? While it may not seem like it on the surface, the game Doki Doki Literature Club makes excellent use of file types, folder management, and some clever coding to hide a wealth of hidden lore and information just below the surface. However, despite all appearances this game is a psychological horror game, and a full list of content warnings about it can be found here, so do take caution before diving too deep. 

From a surface-level reading, Doki Doki Literature Club is a cute visual novel-esque dating sim where the player chooses to date one of the girls in the club. While the first playthrough of the game is fairly tame, it’s in the second playthrough where the majority of the visual glitches and changes can be seen in the interface, although they are present from the beginning. If you open up the game files for DDLC, there are a number of unusual file types and conventions that hold hidden meanings or messages for players to discover, showing the thought process behind Monika and her attempts to make you love her. 

While some of the files are set to appear as text documents after significant in game events, the main ones in need of decoding are the unique files for each of the characters in the character folder, which have the made-up file extension of “.chr”. However, by altering the file type, users can decipher what’s being said. The easiest one to start with is yuri.chr, which when opened in a text editor reveals a long string of numbers and letters. This line of text is encoded in Base64, and when converted reveals a creepy-pasta short story written by the game’s creator Dan Salvato in 2015. While an interesting story to read, we’re not done yet.

The next file in terms of complexity is natsuki.chr, which will require a couple more steps to solve. Looking at the file in a text editor shows a number of visual pointers towards the file originally being a .png file, and when opened as such, a strange, inverted picture is shown. After much manipulation, the image can be inverted again and UV mapped onto a cone or sphere to reveal a strange woman’s face. While it’s unknown for sure who this woman may be, fan speculations point towards a character mentioned in The Portrait of Markov, the in-game book that Yuri attempts to introduce the main character to in the first act. 

In a similar thread, the monika.chr file can also be converted into a png, revealing a red ring surrounding a square full of black and white pixels. Those pixels, when converted into the appropriate string of binary, can then be converted into alphanumeric text to show a similarly garbled string, but this time more reminiscent of the yuri.chr file from before. Throw that through our Base64 converter from before and you get this text document, written from the perspective of the in-game Monika, alluding to a number of unknown terms and events such as the Third Eye.

And finally, the sayori.chr file. Unlike the others, this file needs to be opened as a .ogg audio file, which results in some random sounding noises. However, by applying a spectrograph (an audio visualization tool) to the file, a QR code is revealed, leading to a site called projectlibitina.com. While this site doesn’t appear to have any further information encoded on it, it does show an interesting text document, recording the medical studies on an unknown 3 year old named Libitina and tests related to the Third Eye.  

And there you have it! Each character file breakdown and decoding in Doki Doki Literature Club. Full credit for cracking the original codes goes to reddit user Mithost, who has their own full analysis of their process here, as well as the DDLC fandom wiki for their immense help in tracking all of this. A full list of hidden files and Easter Eggs can be found on the wiki here. Another interesting interpretation of what all these files could mean can be found on The Game Theorists YouTube channel, which helps to visualize some of the steps mentioned above, even if the theory itself has since been somewhat disproven.

Happy hunting!

Edit/ Update: 9/12/23

DDLC has received a lot of love since writing this article, including an additional game with even more content called Doki Doki Literature Club Plus!, with more poems, more cutscenes, and even more lore and hidden secrets. While I have yet to play it myself and do a deep dive of my own, please leave a comment if you ‘d like me to do a deep dive into this game, which was released June 30th, 2021. The steam page can be visited here if you’d like to investigate on your own, although all the same warnings apply to this game as it does to the original.