As this article, weirdly on LiveScience shows, some people seem to think that video games are a new form of story telling. They are not. They do not "free" story telling from the shackles, because story telling is inherently a one-way street. If the person listening to the story becomes involved, they must be involved within limits else it turns into role-playing... which is why role-playing games are called role-playing games. If the ending changes, it is not the same story.
World of Warcraft is not a story. Yes, there is an overarching story that drives many of the major events, but millions of players have nothing to do with that. They spend all of their time wandering around the open world, "writing" their own story. Yes, there is a narrative to it, but a story must have a purpose; it must have some end. And in games, that some end must be pre-determined. And even with games where there are multiple endings, there is always one ending that is counted as the true ending, which is usually the one that takes the longest to achieve and must match a set number of variables in the game. Unless you count Silent Hill's "dog" ending.
For example, if we wanted a game to be a real interactive story, there would never be something like a "game over" state. All endings would be a true ending. But in many games, you can die within the first thirty seconds of game time. To call that a legitimate ending would be absurd. There must be limits. In a real story, there are no limits, only a creative vision. It is obvious why this is so: a player can easily exceed the limits of a created world, because any created world must necessarily be finite.
Games will never be pure stories because they must be within the limits of game rules. For example, I love Halo. I read the Halo novels like Fall of Reach. While far from sci-fi genius, they were decent fluff. The problem is that the stories didn't make ANY sense in relation the game. The description of the super-soldiers (of which you play one in the game) is so beyond anything, that they would have been an unstoppable juggernaut. Strong enough to lift cars. Can run at 60mph.
Perhaps a more famous example, at least in the world of video games, is that of Final Fantasy VII. This was an era-defining game. It is frequently held up as the first truly cinematic attempt at making a video game. It also includes one of the most famous deaths in all of video-gamedom: Aeris. Only, according to the rules set out by the game, it doesn't make sense. On any given play-through, Aeris could have died dozens of times; you could always resurrect her with a spell.
Why should her scripted death be any different? Because it was required by the story. There are some games that try to get around this, by making in-game deaths permanent, one that sticks in my mind is the (old) game Gain Ground. But that was part of the game. Everyone understood the rules because they were communicated explicitly to the player. In a narrative game, if deaths are always made permanent, the player is left in a state of confusion. Should they restart? Is this death avoidable? Is a death at this point necessary?
You'd have crazed players replaying the same part of a game over and over in an attempt to save everyone's life. Conversely, you can have players who charge through a game with reckless abandon, and are left with no one alive, crippling the possible story in that way.
No, I'm sorry. Games are and always will be an imperfect story medium. They are no more liberating from the shackles of story requirements than Choose Your Own Adventure books.
Granted, there are advantages to this. A game should not be seen as a story. It should be seen as a game with rules where certain narrative bits are essentially rewards for completing tasks. To go back to the Silent Hill example, that dog ending doesn't make any sense. It's absurd beyond reason. And that's great! In a real story, it would be bound by the limitation of having only a single ending, which in the terms of a story isn't much a limitation, but it's still a limitation as regards entertainment. In a Choose Your Own Adventure sort of concept, the author can write tons of endings, some of which make no sense, simply because it's funny.
Working toward surprises, hidden rewards, undiscovered narrative elements, it's all part of experiencing a set narrative more fully. For example, people love to discover unfinished versions of books or movies. Deleted scenes, unfinished scripts, all of them are gobbled up by dedicated fans of something. They do this because it is the exact same process as going through a game and finding hidden bits of the story. It is a narrative that isn't simply delivered. It is a narrative discovered. That is what makes games both less and more than a book or a movie.