can we get a new category for the actual arcade game? The new co-op leader for Teenage Mutant Ninja Turtles Arcade 1989 is run on emulator, and 4 player isn't even an option

I'm personally all for separation, but I don't think separating arcade from emulator is the way to go. I would personally, however, campaign for separate categories of 2p co-op and 4p co-op.

how do I go about asking for 1 - 2 - 3 - and 4 player category

Ask one of the mods. I believe at least one of them is still active.

Co-op now split into sub catagories per request. The "platform" section describes what version was used aka Arcade being original arcade hardware, and Arcade[emu] being emulated on PC or by other means