Plutonium

@qntm Yes, but only in Windows. Since you are playing LAN you do not need to open the port to the world, just your home network. You can find a decent article on how to do so here. Just note that the game uses UDP, not TCP (which is selected by default).

Then you're probably missing dlcs? Run piry in your bo2 folder, it'll download them for you and skip over what's already downloaded.