The basic element of any video game is challenge. You can omit any other element and still identify something as a “video game.” You require no graphics for text-based adventure games. You require no music in your games. Stories can also be completely done away with. But think about a video game without any challenge? Not in the sense of not posing any challenge, but rather not putting you against any task, no matter how menial? Notice how I don’t say “overcoming a challenge” as being another basic element? Well, if you can’t overcome a challenge in any conceivable way in a game, then it’s a bad game, simple as that, but it’s not a necessary element to make one.