I am confused about multiplayer. Does it require more than one computer with this game downloaded, or does it require one computer and multiple controllers or something?
Sorry for the very late reply. Same computer multiple control pads.
are ps4 controllers compatible?
You would need to download custom drivers to make them interact with the computer. I think you are also supposed to download a program like "xpadder" or "joytokey" to map the control buttons to keyboard.
I have never done this myself (I use third party controllers that are already compatible).