I started work on a project called "PK2SDK" (Pekka Kana 2 Software Development Kit), which aims to document/compile all the technical aspects of the game.
Stuff like the level file format, the sprite file format, how the graphics work, etc. So that people, that want to create their own level/sprite/save file editor, have easy access to the information needed. Instead of looking through the source code and translating everything.
This project also contains premade libraries for (hopefully) all types of programming languages, so that the developer doesn't have to worry about anything and can just get to work directly. It's supposed to make it as easy as possible to create new programs, so that PK2 may live on for a long time!
If you know any programming language, feel free to create a library in it and put it in the Github repo!
You can of course also help out with the documentation, here is an example of how it should look like:
Indeed, I'd like PK2SDK to document the file structure/format, though. There are libraries for loading these files for most languages, but I think it would make sense to document it separately, so that this information is always available. Just in case.