After dealing with the game mastermind, Gi-hun dyes his hair bright red like the guards' outfits, though that's probably not connected.
This is the game used by the recruiter at the beginning of the game.
He kept on losing the game and the members could not help but to celebrate his defeats.
That film itself is based on Japanese manga.
Gi-hun, Sang-woo, Player 001, and Player 199 team up.
Other games played are fairly obviously real, including marbles, tug-of-war, and Red Light Green Light.