Playing Co-op mode in Metal Slug on Nintendo Switch is not set by default that is why whatever configuration you made in Metal Slug controller settings didn’t help it or activate the second controller. This also happen in some games like Bomberman and other coop games in Nintendo Switch.
To activate coop mode in Nintendo Switch specially in Metal Slug, check our step by step instruction below.
How to Play Co-op mode on Nintendo Switch Metal Slug
First, you have to open Controller Settings from the home screen of your Nintendo Switch.
Now, select and open Change Grip/Order. This is where we set the controller configuration.
Then to activate Two players mode, you have to press the L + R button of your Left Joy-Con.
Once done, do the same on the Right Joy-Con controller. Press the L+R.
You may also add up to 4 controllers, if you have additional pair of joy-con or a Pro controller. Once done just press the Down Arrow button on the Left Joy-Con or B button on on the Right Joy-Con. This time it will show two icon on the bottom of the screen that it is properly configured for Two Players mode.
Now you can open Metal Slug game and enjoy playing Coop mode with your friends.
If you have alternative method to activate coop mode or still have problem doing our step above, please let us know and leave a comment down below.