Making the rounds has been a two hour Youtuber doc by Stop Skeletons Fro Fighting about the construction of a 16-player Faceball 2000 game. Here is the video, but don’t feel you have to watch it yet:
The video refers to a shorter video (19 minutes) by Zarithya, who solved some particular technical issues that made the 16-player game possible. If you’re in the mood for the full journey watch the above video; if you want less of your day consumed, try this one:
The gist: Faceball 2000 was a console (and portable) recreation of an Atari ST game called Midi Maze. Midi Maze was probably the first true FPS. Faceball 2000 got releases for multiple platforms, but the first, and most impressive technically, is probably the Gameboy version.
Developer Xanth Software F/X had a 16-player version of Gameboy Faceball working internally with special cables. Nintendo wanted them to support their new four-player adapter, but the mode that allowed for 16 players with the rigged cables was left in (it still works with an ordinary Gameboy link cable, jut limited to two players), although the devs noted in a 2005 interview that they had only managed to test it with up to 10 players.
Zarithya managed to figure out a way to play it with higher player counts with minimal extra hardware, and also discovered, and fixed, a bug that made 16-player games impossible with the code as released. It’s a pretty accessible explanation, you can probably understand it without much of a technical background.
That’s the main point; for the full story, the videos above are available. Enjoy, if you have the time!