If I can play it, then it is a game.
and to define what playing it is, it would require significant interaction from me that can affect and change the state of the thing that result in different resolutions every time would make it a game. for example chess is a game because you can move the pieces on the board against an opponent. I could win, lose, play to a stalemate, or the game could even end unresolved due to outside factors. In the same way a videogame can be played different ways: I could finish the level/area/section, I could fail and get a game over, I could speedrun the game, I could play with or against other players.
It is different from say a movie or a book that will have the same resolution everytime i watch/read it.
(yes i know about edge cases like choose your own adventure novels or the clue movie, oh and that one time dc held a reader vote to kill off jason todd in 1988, but I would call those exceptions that prove the rule)
Therefore, one could think of games as a sort of collaborative effort between the creator and player, where they are talking to each other, versus other mediums of art where the creator is talking at the viewer/reader.