https://www.cnet.com/news/netflix-black-mirror-bandersnatch-endings-and-easter-eggs-keep-emerging/

After two relatively inconsequential interactions about cereal and music, the story starts to offer crucial choices that take you to different plot points or assign attributes to your account that determine what choices you may see in the future. These determine the possible passwords you can enter into the locked cabinet in Stefan's dad's office, and they influence the options for how to respond when Stefan calls out "Give me a sign!" when he's grappling with the idea that somebody is controlling him. 

Protagonist Stefan (left) interacts differently with his game programming hero, Colin (center), and Tuckersoft CEO Tucker (right) depending on the choices you make.