Fallout Shelter is a mobile game that took the post-apocalyptic RPG and turned it into a game that's all about managing resources, and it turned out to be a hit with fans, whether that's on mobile or elsewhere like PC, PS4, Switch, and Xbox One.
Now crowdfunded platform Noclip has released a documentary showing exactly how it was made and why it became such a success, and you can watch the video on YouTube right here, featuring famous faces like Todd Howard explaining the process.
Why do you think it was so popular?