The game has been updated to fix issues regarding playing co-op on a keyboard or when playing with a controller+keyboard combo. An important note is that "player 1" and "player 2" use different keys on the keyboard regardless of what setup you use. They are as following:

Player 1

• Move - WASD
  
• Jump - Space
  
• Use - E
  
• Call Companion - F
  

Player 2

• Move - Arrow keys
  
• Jump - L
  
• Use - K
  
• Call Companion - J
  

When playing single player, the controls for Player 1 is used, with the addition of using Q to change character.

If the game does not update for you, you can restart Steam to force it.

Update March 14
To be clear - you can now play the game coop using the following setups:

• both players on the same keyboard
  
• one player on the keyboard, one player using a controller
  
• both players using a controller each
  

If you own a controller that does not work with the game, please let us know.