So I got to the point where I unlocked co-op play, but when I tried hosting a game (set to friends only at first and then anyone welcome) my friend (who also unlocked co-op play) couldn't find any rooms to join, and when he tried hosting I couldn't find any rooms to join either. I have no idea why it doesn't work, and there don't seem to be any posts (and thus no solutions either) about an issue like this anywhere.

I also tried doing remote local co-op but that didn't work either, though I don't know if that's the game's fault or something else maybe, but either way it's pretty lame that neither method works at all.