It's not Chapter 4, It's the branch map of existing chapters.
so You need to find a gold card, then find a gold card reader. for example, You can find gold card reader right before the boss room on Chapter 1. but you need to find a key before you get into the boss room.
so You need to find a gold card, then find a gold card reader. for example, You can find gold card reader right before the boss room on Chapter 1. but you need to find a key before you get into the boss room.