You have to be the last one standing out of 98 other players.
The game is really difficult, but highly addictive.
If you have the Nintendo online service than you cn play this game for free, so there's no reason not to play it honestly.
Conversation 1:
Person 1: Have you played Tetris 99.
Person 2: No, but I was planning to install it later.
Conversation 2:
Person 1: Dude, I just got the victory royale in Tetris 99!
Person 2: Epic!
Tetris shiter is the person who stacks shit into a singlepile/multiple piles. It is mainly used in threats in wich the Tetris shiter (usually the person saying the threat) will stack shit into the other person's clothes/body parts/etc
Person 1: I am going to stack shit into your pantslike a Tetris shiter
Person 2: Oh god