Each player is a line that never stops moving, with two keys, left and right. Touch any line including your own and you are out; last one going takes the round. Pick the players at the title screen and hit space, and note the powerup setting while you are there, because the game is different with them on.
It is best with a keyboard full of hands. Rounds run twenty seconds, the accusations run longer, and the tension of a shrinking space with three people still alive in it does not diminish over an evening. It has been going since 2014 and it plays like something that has been polished by people who kept coming back to it.