I can't play co-op using a keyboard and steam controller.

@ChildofChernobyl

Did you tried to connect the controller after you started the game?

Yes, unfortunately still the same problem. After plugging the controller in mid-game, I'm able to control the same yarny as the one I was controlling with the keyboard previously. Thank you for the suggestion, might you have any other ideas? I updated the controller firmware to the latest version, still no luck. 

You might have done this, but if you go to the start menu, did you select the option to add second player on keyboard? If not, try to see if that works.

Also the option sometimes only appears if you open the menu, scroll down the options with the keyboard and then do the same for controller not closing the menu at all. I attached a photo after I made mine appear by scrolling with both keyboard and then the controller.

@holger1405Not sure exactly which of your recommended steps addressed the issue since I used the shotgun approach instead of trying one by one, but I am no able to select "add another player on keyboard" in the menu. Thank you very much for all your help - it is very much appreciated! Have a great day and thanks again!

 @lunarokz Thanks for trying to help as well, I was able to see the option you were talking about after following all the steps recommended by Holger. I'm happy to see that the community is as willing to help as it is!

@ChildofChernobyl

Glad that it worked.

You're welcome, have fun Gaming!

Hello friend, could you please explain to me better how you can make the option appear in the menu bar????? It is that no matter how many things I do, the option to add a friend does not appear :c

To play both characters on just your PC (I'm on Windows 10), You must have a keyboard and a gamepad, or (I think, 2 gamepads works as well I've heard). Two keyboards won't work unless you emulate one of them to be a gamepad (from what I've heard). My solution; Download DroidJoy app on your phone (that's what I use), or whatever emulator you like, and use your phone or both your phones as gamepads. It'll ask you to go to their website, download their server and use it. (It seemed like I had to be in the game before connecting the phone as a gamepad to the server) So once in game, connect your phone as a controller, and then in the menu in the game, you should see the option to connect another controller to play multiplayer locally.
Cheers, best of luck to all!