I may be wrong, but usually what it says there is something like 2-4, 2-6 etc as in:
You can play with 2 to 4 players.
So in the case of 2-2, it just means you can only play with 2 players. It's a weird way of wording it though..
I think tag mode was deconfirmed a while back, assuming they aren't keeping it as a surprise or something.