The largest folder in particular is the sprites folder.
Before going into depth, here is an important note you should know.
Due to the way the game functions, content can be loaded from both the game's /resources/ folder and from its AppData folder.
Content inside the /AppData/Local/ folder have priority over the folder within the installation directory, which is the /resources/ folder.
You can find /AppData/Local/ folder by following these steps.

1. Open your Windows Explorer
2. Type %appdata% into the directory bar on the top
Optional: You can also open the folder by pressing Windows Key + R and typing in %appdata%.
3. Once inside the the folder, you may be inside a folder called Roaming
4. Go up one level out of that directory, you should be in the Local Folder instead now
The game's AppData folder is located in this file path AppData\Local\Ghosts_and_Japes
5. You now should be inside the game's AppData folder :)

If you've played at least up till the 2nd floor within the game, a new file would be within the folder called main.sav
It is encoded in Base64, if you wish to edit your save file.
You can use a website such as this to easily edit the Base64 encoded save file.
When any permanent flags are set, these will go into this folder within /resources/house/.

Now it's time to explain /sprites/.

=== /_progen/ ===

In here, every type of room is stored.
The naming of them is important, as most of the sprites with how they are labelled.
If you want to add a room of your own, you must use the specific colors and name them in a certain way.
Beside the README.txt is another file called KEY.png, this file can be used to color pick the exact color code, every color tells the game what to place where within your custom room, go wild!
More info about the KEY.png can be found here: KEY Colors.

If you plan on using a tool, please make sure any anti-aliasing is disabled!
We recommend using Aseprite for making the rooms.
Please use EXACT colorations as per the KEY.png file, it is also recommended that you draw using the brush size at 1 or the pencil tool, to make it easier for you to make rooms or sprites.
When naming your custom rooms, you must name them with the prefix "spr_progen_".
If it has this prefix, the game's room compiler will recognize it.
After this prefix you must specify what kind of room this is.
Here is a list of some room types you can choose from, with a brief explanation of what they are:

• branchb - Room with doors that go up, right, and left.
• branchl - Room with doors that go up, right, and down.
• branchr - Room with doors that go up, left, and down.
• brancht - Room with doors that go left, right, and down.
• cornerbl - Room with doors that go up and right.
• cornertl - Room with doors that go up and left.
• cornertr - Room with doors that go left and down.
• cross - Room with doors that go up, down, left, and right.
• hallh - Room with doors that go left and right.
• hallv - Room with doors that go up and down.
• roomb - Room with a door that goes up.
• rooml - Room with a door that goes right.
• roomr - Room with a door that goes left.
• roomt - Room with a door that goes down.
• start - The starting room of a floor.
  About "start", it must have a door that goes left, right, and upstairs.

Aside the room sprite files, you should normally see files called .progen.
These files are pre-compiled versions of the room sprites that are stored into a file.
If they are deleted, or the corresponding .png sprite file in any way, the game will automatically regenerate the files for you.
Even room sprites that you added yourself!
It is recommended you structure your custom rooms in the exact way that you see some of the existing rooms use.
If a room type requires certain doors, you should include those, or else the game is probably going to break, crash or become unplayable.
Your room sprites also don't need to be even dimensions - you can make them 16x16, 16x29, 31x8, whatever you want.
Keep in mind though, that the larger your room is, the more it can take to have the game compile it, the game may perform worse inside of them.
When the game compiles a new .progen file, it will not go into the installation directory's resource folder.
Instead, it'll go into its /AppData/Local/Ghosts_and_Japes/ directory, as explained previously.
Also, if you delete a .png file, the game will not add it to the rooms that will generate in-game list, even if the .progen file exists.
Now, if you want an example for naming the files, here is one:
spr_progen_hallv_my_cool_hall.png
To quickly recap, you need the spr_progen_ prefix followed by the type of room it is, such as the example used hallv.
Then you can put any name afterwards to make it distinctly named from other rooms within the folder.
Once the game is ran once, it should generate the .progen files for you inside the folder /AppData/Local/Ghosts_and_Japes.

=== /(insert enemy name here)/ ===

You'll see every enemy's sprites are stored in their own folder with their name.
Them being named this way actually doesn't matter, it is for organization purposes, keeping everything dust free. You could, for example, have one of the custom ghosts named cool_ghost but it loads the sprites from the uncool_ghost folder just fine.
Each and every enemy is required to at least have these sprites:
eat, gameover, grabbed, idle, MASK and painting.
Another important thing that is required is that the color used for transparency is the top-left most pixel.
If your custom ghost/enemy, or any other sprites, is rendering weirdly in-game, check the color you used for transparency. Also, any animated sprite needs to have square-shaped frames.
So, if you wanted an animated sprite with 4 frames, and your enemy is 16x16 pixels, the sprite sheet should end up being the size of 64x16. The dialog portraits are completely optional, if you want your custom ghost to have a voice at all.
The names are generally self-explanatory; here is what all of them mean when they are used:

• eat - When the enemy is currently attacking the player.
• gameover - Displays after the enemy has defeated the player.
• grabbed - Frame 1 displays when the enemy is stunned by the player's flash.
  The whole sprite animation plays while the enemy is being siphoned by the player's wand.
• idle - The general animation that the enemy uses.
• MASK - The enemy's interaction range.
  If the player's MASK collides with the enemy's MASK, interactions can happen; such as the enemy beginning to attack the player or the player being allowed to talk to the enemy.
• painting - When an enemy spawns in a room, they are able to replace pre-existing paintings with their own.
• portraits - Optional: Can be used in the strings_en.txt file to make a textbox sequence render that portrait.

=== /painting/ ===

Inside of this folder, random paintings that are placed around the household are loaded here.
These MUST be named with the prefix "spr_obj_painting_".
Anything after that is fine though.
Once again to remind, make sure the top-left most pixel is the color you want to have for transparency, or it will render not as desired in-game.
So, as an example, you can have a painting sprite file named "spr_obj_painting_my_coolpainting.png"

=== /player/ ===

The sprite names for the player character are hard-coded into the game.
the portraits are optional as before, as they are only used for the textbox sequences seen in the strings_en.txt file.
If you are going to make a custom player, you must them in the exact same way as you find them in the folder.
The player must have at least these sprites:

• spr_player_down_idle
• spr_player_down_move
• spr_player_generic_gameover
• spr_player_ko
• spr_player_left_idle
• spr_player_left_move
• spr_player_MASK
• spr_player_right_idle
• spr_player_right_move
• spr_player_up_idle
• spr_player_up_move

The player's MASK sprite is used for the player's interaction collision range.
If it is overlapping with an enemy's interaction mask, interactions such as attacking or chatting can occur.
The generic gameover sprite is used for if the player is somehow defeated by something other than a ghost.
Basically you get the Generic Game Over if you reach 0 HP while outside of a ghost.

=== /projectile/ ===

All projectile animations are loaded from here, you can add your own projectiles to your custom enemies.

Now, the /sound/ folder.

=== /sound/ ===

This folder is simple; if you want to add your own custom sounds for your enemies, their projectiles, or dialog, you place them here.
All they have to be is in .ogg format.
If they sound wrong in-game, make sure your sound file does not have a strange sample rate.

=== /lang/ ===

The /lang/ folder is where nearly all text, aside from a few hard-coded in-game ones, are stored inside of.
You can also make and add your own new dialog in here with certain special effects.
Per-enemy dialog should be placed in their own respective JSON files, unless there's something specific you need a dialog they speak to do.
I will explain how our text formatting system works, strap yourself in for some learning.
Here, I will list an example text: The first value, '"txt.cool_string_name.0":' is the text's identifier.
This is to be used in the enemy JSON files to make it actually load and be used in-game!
The second value is where the actual text contents are.
There are a few text formatting options to make your dialog more fun to read.
I will explain them in order of how they appear in the example text above, in order, then list all of the text formatting options below that:

• [speaker.spr_portrait_player_neutral.snd_vox_player] - Here, you can set who is speaking aloud the dialog.
  If you remove this entirely, it will be read generically by the game.
  After the first ., the name of the portrait sprite must be specific.
  Then, after the second ., you specify the voice sound they use for reading their dialog.
• [color.rgb.0,255,0] - You can color your text to any color by supplying RGB values.
  In the example text, the text Hello, would show up in green.
• [wait.amount.5] - How long to wait before reading the letters after this tag. In this case, it's 5, which means it waits 5 frames. This game runs in 30 FPS.
• [motion.wavy.20] - This moves every individual letter it affects in an orbit around its origin point.
  The 20 means its orbit rotates 20 degrees every frame.
• [reset] - This is used to reset and remove all previous text formatting that were applied to the text. So, after the green Hello, that had wavy letters as well, the text after the [reset] would no longer have wavy motion or green applied.
• [motion.rando.1] - Moves each letter in a random direction around its origin point, which has the effect of looking jittery. The number specified, 1, means each letter moves between -1 to 1 around the letter's origin point on its x- and y- axis.
IMPORTANT!!!
With these text formatters, you should never put them at the very end of a string.
If you want to do this, you must add a blank space directly after it.
If the string ends with a formatting tag, but no space afterwards, the game will crash once it reads the text formatter.
This is an important none, for things such as enemies talking to you automatically while attacking you.
For those, you will have to place, for example, a [wait.amount.30] afterwards or else the ghost's dialog disappears immediately as soon as the ghost is done talking to the player.

Next, here is a list of every single one of your text formatting options:

• [speaker.sprite_name_here.audio_name_here] - With this tag, you place it at the start of a text, and that will tell the textbox to render sprite_name_here on the left inside of the textbox, and play audio_name_here for every time a letter (a-z) is read in the textbox.
  This is used to make text be spoken by a character, for instance.
• [color.rgb.255,255,255] - With this tag, you can color text after its position in the text using RGB values separated by commas.
  With a value of 255,255,255 this results in the text after it being rendered as white.
  Note that by default, in textboxes with no color tag, the text is rendered in white.
  This applies to after a [reset] tag is read.
  (see below for more info on [reset])
• [motion.motion_name_here.value] - There are a few different options with this tag.
  For the first argument, motion_name_here, you have these options:
 - rando makes the text have a jittery appearance.
value dictates how much the text jitters away from its origin point, in pixels. Values MUST be whole numbers (integers).
 - wavy makes the text orbit around is origin point.
value dictates how many degrees to rotate around its origin per frame. Note that the game runs in 30 FPS. Value must be whole numbers (integers).
 - singsongy is the exact same as wavy, but it will not move left or right. Value must be whole numbers (integers).
 - wobbly is the exact same as wavy, but it will not move up or down. Value must be whole numbers (integers).
• [wait.amount.value] - Use this tag to indicate when the text should wait a certain amount of frames before continuing.
  Replace value with the number of frames to wait before continuing to read the text.
  So, for example, [wait.amount.30] would make the textbox wait 30 frames (or 1 second, since the game runs in 30 FPS) before continuing to read.

Finally, depending on the contents of the text identifier key, the textbox can behave differently.

• Text identifier ends with .choicec - You can specify choices the player can input, at the end of the string, separating them with |
• Text identifier ends with .grab_player - After this text finishes, the initiator of the text (if an enemy) will grab the player and begin attacking them.

=== /house/ ===

The /house/ folder is where certain specific permanent game flags are set.
At the time of writing this, there are currently 4 "house" files, as I will continue to refer to them by.
These files are files that have no file extension, and continue 1 line of very basic info.
If you can't find a specific house file, check /AppData/Local/Ghosts_and_Japes/resources/house/ and the game installation's directory's /resources/house/ folder.
Here is what each one does currently:

• size - Here, you can specify how large every floor of the game should be.
  It is a default of 16, has a minimum of 8, and a maximum of 3072.
  Note: If you set the value to below 8 or above 3072 will immediately crash the game on loading.
  It is highly recommended you leave this alone, as 16 feels best to play.
  8 means every floor is very short, and 3072 means every floor is gigantic.
  Your computer may crash or be unhappy if you do anything especially in the thousands.
   IMPORTANT!!! 
  The game is probably also impossible to beat with floor sizes that large.
• grave - This file keeps track of how many enemies you have defeated across all playthroughs.
• intro1 - A simple file that keeps track of whether or not you saw the player's intro dialog from playing for the first time.
• item_swap_explanation - Similar to "intro1", keeps track of whether or not you had alternate item hand swapping explained to you yet.
• opt_music - Options menu setting; where the music toggle is stored.
• opt_window_fullscreen - Options menu setting; where the fullscreen toggle is stored.
• opt_window_scale - Options menu setting; where the window scale is stored.