Click E to punch for player 1 and Q for the kick. Click D for moving and W to jump. When you move using the D key it will follow where your mouse is at. Left arrow for punch player 2. Down arrow to kick for player 2. Right arrow to move for player 2. Up arrow to jump for player 2.
I did this and its not my first 2 player game. They both follow the same mouse so I will try and fix the bug later.
