Hello there, fellow survivors!
I have been enjoying and loving this game for years now, but I have had several - to me - rather severe issues with the game that I would like to fix for myself.
I am mostly interested in slowing down the speed at which my characters improve their skills significantly (I tried using the “slow learner”, “pacifist” and “good memory” traits combined, but was unimpressed with the results) as well as reduce the amount of armor that both, actual armor such as kevlar vests as well as clothing items such as hoodies or cargo pants provide.
Is there a guide anywhere that I could follow in order to administer these changes to my game? Or would I have to first get a PHD at my local college in order to achieve that?
Thank you in advance for any help on the subject matter!
I’m fairly sure that changing armor values is as simple as fiddling with the jsons and changing variables.
As for learning speeds, I believe those are coded into the game and would require you to delve into the code with some knowledge of C++(?).
The Lab subforum is all about modding and editing code, I’d check there for more help and resources!
Hopefully that helps a bit.
Modifying particular items can be done just by modifying text files. Go to data/json/items/ and edit the relevant files in any text editor. You want to lower the material thickness values. There’s a ton of them, so you’d better have a good way of doing so (unless you only want to nerf a small number of items).
Or you can recompile the game and modify values globally. I recommend the second option, even though it requires non-zero computer skills.
The learning speed change would require recompiling the game.
First get the source (preferably with git, so that it’s easier to update, but you can just get the zipped source here: https://github.com/CleverRaven/Cataclysm-DDA/archive/master.zip )
Then get the tools - I heard most people use CodeBlocks to compile the game.
Unpack the source and open the CacaclysmWin.cbp in CodeBlocks.
Modify the game. The parts of code you’d want to change are in src/player.cpp (player::adjust_for_focus) and src/item.cpp (item::bash_resist and cut_resist).
Since you’d be introducing very simple numeric changes, that wouldn’t require any real programming skills. Just modify the formula after “return” at the end of the block of code.
Then build the game. It can easily take an hour, but doesn’t require you to look at it constantly.
I love this open source approach! Wow!
if you are to lazy to compile-decompile and you only want to edit/add/remove small things download notepad++ and edit .json files
Yeah, guidelines for modding .json files are here on the forum board, too.
It’s modding season for you, friend! 
Not modding related, but potentially useful to you:
You can turn off certain skills from advancing by tabbing to them in the Character Sheet and hitting enter while they are selected. They’ll still check for recent use to prevent skill rust, but they won’t advance. If you’re interested in a longer lasting “survival horror” experience, turning off your combat skills when they reach 3 or 4 is an effective handicap.