For a while, I have been organizing levels into folders, mainly the "cache" folder that online levels download into when you join and play on a server, since it frees up space in the main JJ2 folder.

However, when using the in-game level browser via Home-Cooked levels or by selecting to play on custom levels in Multiplayer, it only supports viewing the main Jazz Jackrabbit 2 folder/directory, with no option to (from what I know) choose a folder in the directory and browse the levels in those folders.

For this, I was thinking that there could be the option to show folders in the level select, and then by choosing a folder, you open that folder in the in-game level browser and can pick a level like normal, or return to the previous folder by scrolling up to the very top of the list and choosing "Back". All folders would appear at the very top of each folder's level list, followed by the actual level files.

UP! This is an awesome feature idea! An additional idea to this would be the ability to download online levels from that same menu without having to exit jj2 or restart jj2, And possibly, the list could be from J2O with some sort of API!

I concur.

An additional idea to this would be the ability to download online levels from that same menu without having to exit jj2 or restart jj2, And possibly, the list could be from J2O with some sort of API!

Obviously this is a much different and much more complicated suggestion, so trying to discuss both in this same thread won't be very helpful. But Superjustinbros' idea sounds easy enough. It's not going to give you the full power of AdditionalFileFolders, because it only extends to subfolders of the JJ2 folder, but it could still help.

I spent my weekend on this and I've got it roughly working, but I haven't tested it very much because I never actually use the Home-Cooked Levels menu myself, so I'm not the best person to make sure everything is working properly. The only thing changed here compared to regular 5.12 is the Home-Cooked Levels menu, this should be fully compatible with all other uses.

One unfortunate detail is that I had to disable saving for levels loaded from subfolders, because there's no way to include that information in a save file.

Tested and works out great, would love this addition to be official. I also tried breaking it by giving weird folder names, but it seems to work out well.

Three small nitpicks:
1) Visually it could be a nice touch if the map icon jumps in similarly like the jazz2 font. The staticness of the map icons frame 1 of entering home cooked levels feels uncharacteristic for JJ2.
2) It would be nice to see your current folder you are looking into at all times to not get disorientated, maybe next to the "../"?
3) I found myself keep pressing escape to intent to go back one level in the folder, especially when scrolling somewhere midway through, but it goes back to the episode select.

Thanks, that's good feedback! I've implemented #1 and #3. For #2, your current folder (if any) is already displayed in the bottom right corner in big rainbow letters.