So yesterday I downloaded Tetris Ultimate on the Xbox One with the hopes of playing some Tetris with my girlfriend. However, I found it incredibly difficult to figure out how to start a local multiplayer match. The menus say to add members to your party to start a Versus or Coop match, and there’s a box on the right with “friends” in it (it only lists AI players for me right now).
Even though my girlfriend was logged in, she didn’t show up on that list. I tried starting a party via Xbox with her in it, and she still didn’t show up. It turns out, any additional local player needs to press the Menu button (“start”) and then they’ll be asked to select a profile and they’ll be added to the game.
There’s no prompt for this at all that I could find, it was just by dumb luck that we finally figured out how to get her in the game. Hope this helps!
EDIT (25 January 2015): I’ve created a video now if you prefer to see how to add a second player.
avideogamelife 
thanks for this! we were in the same predicament after my boyfriend set up an account so i could play tetris with him. we were stumped until i googled and this came up. their online matching still leaves much to be desired (last night when we tried it said it would take ten minutes to find a match…lol – and then the counter never moved and we eventually gave up) but otherwise it was fun.
No worries. Yeah I haven’t been able to get into an online match yet either.
thanks for this! we were in the same predicament after my boyfriend set up an account so i could play tetris with him. we were stumped until i googled and this came up. their online matching still leaves much to be desired (last night when we tried it said it would take ten minutes to find a match…lol – and then the counter never moved and we eventually gave up) but otherwise it was fun.
Thanks you ! I was in the same case. It was helpful
Thanks for the tip! Couldn’t figure it out on my friend’s PS4 until I found this. There is zero documentation for this game available, and it’s main menu sucks!!
Thanks for posting, couldn’t figure it out on my friend’s PS4 until I found this tip.
Yes.. thanks for the video. The thing I find frustrating is that after I do this and sat the game, the computer starts playing the opportunity ends roll. This game is weak.
Once the second controller is on, you’ll see P2 (player 2) on the right underneath party play. Then you just click on battle.