Follow Colin Or Visit Dr. Haynes
Development of Bandersnatch proves to be difficult, and after long days of working nonstop Stefan becomes incredibly frustrated. His dad enters his room and tries to persuade him to go out to the pub. At this point, you are given a choice to either Throw tea over computer or Shout at Dad. If you choose Throw tea, the game will force you to go back and make a different choice - your first introduction to the idea that it's not actually possible to destroy Bandersnatch.
After choosing the option to Shout at Dad, Stefan will be forced to go out to lunch. However, upon waking up in the car he finds he has been brought to Dr. Haynes' office instead. Stefan's dad tells him he needs to talk to his doctor, but Stefan sees Colin passing by. At this point you are given the option to either Follow Colin or Visit Dr. Haynes. If you choose to Visit Dr. Haynes, Stefan will attend a therapy session during which he talks about his recent anxieties and struggles with the game. This option also means that Colin will appear later in the episode, and opens up different choices in the long-term.
If you choose to Follow Colin, Stefan will be invited back to Colin's apartment, where he meets Colin's girlfriend, Kitty, and his baby daughter, Pearl. Colin offers Stefan drugs as a way to open up his mind and break through his mental block, and you can either say Yes or No. It doesn't actually matter how you answer: if you choose Yes, Stefan will take the drugs voluntarily; if you choose No, Colin will slip them into Stefan's tea.
Following a wild drug trip and a conspiratorial rant from Colin about how the whole world is a game with many parallel timelines, Colin offers to prove his theory. He takes Stefan to the balcony and says that one of them will jump off to prove that their choices are immaterial. Stefan is given the choice of who jumps: Stefan or Colin. If you choose Stefan, he will jump to his death and the episode moves forward in time. Bandersnatch is released, having been finished off by someone else (probably Colin). The critic on the video game TV show mentions that Stefan died in an accident, and gives the game a poor review, with this storyline ending on him rattling off a long list of adjectives (weird, creepy, bleak etc.) before an option appears to go back.
If you choose Colin, he will jump to his death as Stefan watches. Kitty comes out to see where he is, and is horrified by the sight of his body. Colin then turns around and sees the monster from Bandersnatch, Pax, before waking up in his dad's car on the way to Dr. Haynes' office. It's unclear if this is a reset, or if the visit to Colin's apartment was merely a dream. However, choosing to let Colin jump means that Colin will mysteriously disappear, and will not be present in later scenes.