Wherever Stanley Parable is a game or not, isn't really important. Someone could make the argument that open ended games, without a clear winning or completion state aren't games, but instead simulations.

Someone could argue that the winning or completion state of Stanley Parable is seeing all endings.

Other people say that to be a game, you need some kind of adversary or challenge to overcome, but that would depend on the definition of challenge. Is figuring out what to do in order to see a ending you haven't seen before a challenge? If not, that would exclude many other genres.

So I just do not want to down the road of making useless distinctions, and be liberal in my understanding of words, and just ask if something is not clear.

I just call Stanley Parable a game, because the creators call it a game, you can buy it and games similar to it for game consoles and on Steam under the game category. Wherever you can or cannot find enjoyment in experiencing it, does not depend on wherever it is a game or not.