MODDING THE GAME WILL ERASE ALL YOUR SAVES AND RESETS YOUR SETTINGS. IT'S ALSO RECOMMENDED TO FINISH THE GAME ONCE BECAUSE SOME MODS CONTAINS HEAVY SPOILERS

• First, you'll need to download Oneloader. You can use this link to download it : https://github.com/rphsoftware/OneLoader/releases
  
  
• You have to decompile it in the OMORI file (to access this folder you have to do Steamlibrary > steamapps > OMORI) and replace the existing files (it will replace the "www" folder)
  
  
• You can launch the game to see if everything is done correctly
  
  This is how it should look like :
  
  

To add a mod, first you'll need to download the mod you want (you can download it here : https://mods.one/ )

Then you'll need to place the compiled mod (Don't decompile it) in the mods folder (to access this folder you have to do Steamlibrary > steamapps > OMORI > www > mods)

YOU HAVE TO CREATE A NEW GAME, LOADING A SAVE WOULD CAUSE A CRASH

"Castastrophic failure while loading the modloader" :

• Uninstall - Reinstall the game
  
  
• Verify the integrity of game files by going Properties - Installed Files - Click the "Verify integrity of game files" button.
  
  
• Download Oneloader folder again but on this site https://mods.one/mod/oneloader

Error while saving or loading a save :

• Just install this https://mods.one/mod/modsavefiles
  
  
• Place it in the "mods" folder

Error while saving or loading a save even with the mod save file fix :

• Try with this one https://mods.one/mod/saveloadplus it should work

IF YOU HAVE ANY OTHER ISSUES

Write it under this guide or dm me, I'll do everything i can to help :)