clearstream
(He, Him)
Played according to RAW, it is a game. The way you can tell is to read a book, then read it again. Any words changed? Anything happen that didn't happen before? Then try playing through a D&D adventure twice. Of course there will be broad and perhaps important similarities, but there will be innumerable and perhaps equally important dissimilarities. Provided you have a good memory, with a book you can predict exactly what happens after the words "and then the hero swung his sword at the skeleton". It's the same every time. With a game, you can't make that prediction. You can make a good guess - "the 2nd level Fighter with +5 to hit swung his sword at the AC 13 skeleton" - chances are he hit. Sometimes he doesn't.D&D is a game: we play characters, roll dice, try to win and not lose.
D&D is also a story: characters are travelling on an adventure in a fictional world, with dialogue and social interaction, plot hooks, etc.
In your opinion, is D&D more story or more game? What are the consequences of that?
Another reflection on the distinction is to think about a game of Chess. Imagine we watch one, recording all the moves. After the game is completed, we have the unchanging story of the game. When black moves her bishop there, white always moves his rook there. Before the game is completed - while it is in play - we can't make such a prediction. We can make a good guess, if we know the players and the lines of play, but if we get those same two players to play another game, the moves are unlikely to be all the same.
In essence all stories are retrospectives, while games explore an unknowable future.