The briefing
The whole floor is a grid of lit tiles and the screen overhead calls a colour and a countdown. At zero, every tile that is not that colour drops out of play and takes one of your lives with it if you are standing on one. Rounds get shorter, the safe colour gets rarer, and by the end you are reading the floor and moving before the call finishes. Two people can play it head to head, or a group can run it as last one standing.