What's the Story? (Or Why My Game Character Has Amnesia)
Traditional media like books and cinema are fundamentally different from games. While most traditional media have a passive audience that cannot change the outcome of the story, games have active audiences that have choice and thus, the ability to influence the story.
Imagine a movie in which the hero meets with an accident inside a lab. As a result of this accident, the hero gains bug like abilities and the character's motivations propel him to save the world. Compare this with a game- the player controls where their character goes. What if the player never goes to the lab? Would this character still live out its destiny? What would happen to the story?
A story is the observation of a series of actions, so while our player may be carving out a novel story, it might not be the most interesting one. A good story within a game would be one where for every path through the series of actions, an experience is scripted beforehand by a narrative designer. This becomes a daunting task for the narrative designer because true choice afforded to the player means they can do anything.
Here's where the amnesia comes in. Amnesia allows for the story to already have taken place before the player start engaging. If a character wakes up on a battleship, the player intuitively understands that their character is a warrior and they aren't given much choice to change that about their character. The player could go anywhere on the battleship, but they will always carry a blaster and always have to shoot or be shot at. This helps limit the scope of the game and give greater control to the writer/ narrative designer to elicit the exact emotion they want to draw from the player.