complete chapter 1, left or right player doesn't matter
complete chapter 2, left or right player doesn't matter
complete chapter 3, left or right player doesn't matter
complete chapter 4, left or right player doesn't matter
invite a friend to your room
chapter 7: refill the tanks with colour, left or right player doesn't matter
complete chapter 5, as left player
complete chapter 5, as right player
complete chapter 6, as left player
complete chapter 6, as right player
chapter 7 right player: get your partner out of the tube (gear puzzle)
chapter 7 left player: get rescued by your partner (leave the tube before you drown)
complete chapter 7, as left player
complete chapter 7, as right player
complete chapter 8, as right player
complete chapter 8, as left player
complete chapter 9, as right player
complete chapter 9, as left player
complete chapter 10, as right player
complete chapter 10, as left player
choose to sacrifice others
choose to sacrifice yourself