For Project64.
Click Options. Configure Controller Input.
Click Player 2 tab.
Check Controller is plugged in.
Click Setup.
Assign buttons. (is best if you have a controller for this. Two players on keyboard for N64 is tight).
You can do the same for Player 3 and 4 if you want.
Click OK.
Press F1 to reset. Or Click System Reset.
Now you can play multiplayer.
This topic has become multiple subjects. Those instructions are just to play multiplayer Golden Eye on one computer. N64 does not support netplay. If you have dual monitors you can split the screen.
Horus I'm not sure if you are even interested in netplay or not but for N64 netplay the only option would be a third party VPN. I have not tested any of these myself but in theory if you have a fast internet connection and all players are somewhat near each other then they should work.
5 Free VPN Clients to Play Multiplayer Games With Anyone Over Internet
---------- Post added at 01:49 PM ---------- Previous post was at 01:47 PM ----------
In Mupen it is more difficult.... More on it later.
---------- Post added at 01:52 PM ---------- Previous post was at 01:49 PM ----------
In Mupen, if you can, try plugging in 1 or 2 controllers before launching the game. That might auto enable multiplayer in this game.
If you don't have at least 1 controller I don't see how you plan to play a 2 player N64 game. Keyboard would be way to crowded.