Responses

Multiple cassettes for each player as you can see, in that one scene where they took the blue haired's cassette tape(he is unintentionally putting in the tape every prologue in car remember?) after that the blue haired does not remember anything anymore and the same goes for the character with glasses
Cassette tape= save their progress
save their progress= save their memories from previous games
Their memories from previous game= breaking the 4th wall, it means knowing they are a character in the game
without inserting the cassette tape= They no longer knows they are a character in a game they became a regular NPC
additional: If any of you plays video games there is a "Load game" and "New Game" option, click the load game and you will see your progress where you left it off completely intact, so the inserting the casette tape into the music player is equivalent to "load game" option.