So I've been doing what I said I would - splitting the code into far more manageable chunks spread across many files. I'm not quite finished yet. Initially there were about 10 files at most, covering the data editor, the competition engine, the game database and so forth. All of them pretty large to the point where they got difficult to manage.
I'm not quite done yet but currently the total stands at 109 files, each one typically containing a single function and a few of the files have more, smaller functions that splitting seems a bit silly.
It's a ridiculously big game that doesn't even have some very important bits. Tsk.
That's my excuse for all this time. It's fucking huge. Live with it.