To answer your question as to where the “Nun” part of this “game” comes in; it only happens if you choose “Give me something different” at the end where Jane changes her mind about being with John and decides to become a Nun.
The Angry Video Game Nerd is an internet legend, he's been around since 2004, before RU-vid existed! You picked one heck of an episode for your first time, as this is arguably the worst game he's ever reviewed. XD