You normally can play the Cupcake mini-game by repeatedly dying. Alternately, enter the "Extras" menu and place the mouse cursor in the bottom left corner of the screen for an 8-bit Baby sprite to appear. Click on it to play the Cupcake mini-game.Reaching the Private Room
First, successfully complete the Cupcake mini-game. Then on Night 5, reach the point where Baby guides you through the Funtime Auditorium. When you get back to the Funtime Auditorium, immediately turn right to enter the Private Room. If done correctly, you will hear a voice say "Access Granted".Five Nights At Freddy's 4 reference
In the Private Room, enter "1983" into the keypad for the screens to display rooms from the Five Nights At Freddy 4 house.