: It opens two separate instances of the game and assigns the keyboard/mouse to one and the controller to the other. Setup :

If the native method fails to separate the keyboard from the controller (sometimes they both control Player 1), the Nucleus Co-op mod is the most reliable workaround.

: The game natively distinguishes between the two devices. The keyboard/mouse typically controls Player 1 (left/top), while the controller controls Player 2 (right/bottom). Alternative Method