Novels, poems, plays, short stories -- they all communicate meaning through the ways they use language and how the reader perceives the work as a whole. Even though they are fixed, static texts, vastly different readings and experiences are possible.Is Hamlet sane, or is he secretly crazy even though he thinks he's sane? (After all, crazy people rarely think they're crazy.) Both sides (among others) have been argued, yet it's all focused on the same text. The difference is that you, personally, will find one reading more convincing than the other.
Games, meanwhile, communicate meaning through the ways they use gameplay mechanics and how the player perceives the work as a whole. Even though many of them are fixed, static spaces with only so many choices / branches, vastly different playthroughs and experiences are possible.
